Update to the latest version of rules_python

[parthea]

The error Not a regular file appears when attempting to update to the latest version of rules_python 1.4.1 using the rule here

https://github.com/googleapis/gapic-generator-python/blob/1c6e9a4f460be0dd1eafc55b2eff964651a4e2ac/WORKSPACE#L25-L34

See the stack trace below:

py3133partheniou@partheniou-vm-3:~/git/gapic-generator-python$ gbazelisk run //tests/integration:asset_update
INFO: Repository gapic_generator_python_pip_deps_google_api_core instantiated at:
  /usr/local/google/home/partheniou/git/gapic-generator-python/WORKSPACE:49:13: in <toplevel>
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/gapic_generator_python_pip_deps/requirements.bzl:248:20: in install_deps
Repository rule whl_library defined at:
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/whl_library.bzl:533:30: in <toplevel>
INFO: Repository gapic_generator_python_pip_deps_proto_plus instantiated at:
  /usr/local/google/home/partheniou/git/gapic-generator-python/WORKSPACE:49:13: in <toplevel>
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/gapic_generator_python_pip_deps/requirements.bzl:248:20: in install_deps
Repository rule whl_library defined at:
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/whl_library.bzl:533:30: in <toplevel>
ERROR: An error occurred during the fetch of repository 'gapic_generator_python_pip_deps_google_api_core':
   Traceback (most recent call last):
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/whl_library.bzl", line 306, column 40, in _whl_library_impl
                pypi_repo_utils.execute_checked(
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/pypi_repo_utils.bzl", line 142, column 24, in _execute_checked
                **_execute_prep(mrctx, python = python, srcs = srcs, **kwargs)
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/pypi_repo_utils.bzl", line 112, column 43, in _execute_prep
                repo_utils.watch(mrctx, mrctx.path(src))
Error in path: Not a regular file: /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/pypi__colorama/colorama-0.4.6-py2.py3-none-any.whl.dist-info/RECORD
ERROR: /usr/local/google/home/partheniou/git/gapic-generator-python/WORKSPACE:49:13: fetching whl_library rule //external:gapic_generator_python_pip_deps_google_api_core: Traceback (most recent call last):
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/whl_library.bzl", line 306, column 40, in _whl_library_impl
                pypi_repo_utils.execute_checked(
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/pypi_repo_utils.bzl", line 142, column 24, in _execute_checked
                **_execute_prep(mrctx, python = python, srcs = srcs, **kwargs)
        File "/usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/pypi_repo_utils.bzl", line 112, column 43, in _execute_prep
                repo_utils.watch(mrctx, mrctx.path(src))
Error in path: Not a regular file: /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/pypi__colorama/colorama-0.4.6-py2.py3-none-any.whl.dist-info/RECORD
INFO: Repository gapic_generator_python_pip_deps_googleapis_common_protos instantiated at:
  /usr/local/google/home/partheniou/git/gapic-generator-python/WORKSPACE:49:13: in <toplevel>
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/gapic_generator_python_pip_deps/requirements.bzl:248:20: in install_deps
Repository rule whl_library defined at:
  /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/rules_python/python/private/pypi/whl_library.bzl:533:30: in <toplevel>
ERROR: /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/gapic_generator_python_pip_deps/google_api_core/BUILD.bazel:5:12: @gapic_generator_python_pip_deps//google_api_core:pkg depends on @gapic_generator_python_pip_deps_google_api_core//:pkg in repository @gapic_generator_python_pip_deps_google_api_core which failed to fetch. no such package '@gapic_generator_python_pip_deps_google_api_core//': Not a regular file: /usr/local/google/home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/pypi__colorama/colorama-0.4.6-py2.py3-none-any.whl.dist-info/RECORD
ERROR: Analysis of target '//tests/integration:asset_update' failed; build aborted: 
INFO: Elapsed time: 1.260s
INFO: 0 processes.
ERROR: Build failed. Not running target
FAILED: Build did NOT complete successfully (11 packages loaded, 0 targets configured)
    currently loading: @com_github_grpc_grpc//
    Fetching repository @gapic_generator_python_pip_deps_aiohttp; Running IsStandaloneInterpreter
    Fetching repository @gapic_generator_python_pip_deps_pytest_asyncio; Running IsStandaloneInterpreter
    Fetching repository @gapic_generator_python_pip_deps_protobuf; Running IsStandaloneInterpreter
    Fetching repository @build_bazel_rules_swift; starting
    Fetching ...home/partheniou/.cache/bazel/_bazel_partheniou/158c73e91735c8bd1e202dd9acfefc6b/external/build_bazel_rules_swift; Extracting rules_swift.2.1.1.tar.gz