`zkg create` fails with UnicodeEncodeError when using non-ASCII characters in user vars

[AmazingPP]

Description:

When attempting to create a package using zkg create, I encountered an issue where non-ASCII characters in the user variables (e.g., author name) result in a UnicodeEncodeError. This prevents the package creation from completing successfully

Steps to Reproduce:

1. Run the following command:

zkg create --feature license --packagedir foo

2. Provide the following inputs when prompted:

name: Foo
author: 张三 <[email protected]>
license: mit

Observed Output:

2024-06-27 17:36:44 ERROR    problem during template instantiation: 'ascii' codec can't encode characters in position 0-1: ordinal not in range(128)
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/zeek/6.2.1/bin/zkg", line 2295, in cmd_create
    package.do_instantiate(tmpl, args.packagedir, args.force)
  File "/opt/homebrew/Cellar/zeek/6.2.1/lib/zeek/python/zeekpkg/template.py", line 708, in do_instantiate
    super().do_instantiate(tmpl, packagedir, use_force)
  File "/opt/homebrew/Cellar/zeek/6.2.1/lib/zeek/python/zeekpkg/template.py", line 552, in do_instantiate
    self.instantiate(tmpl)
  File "/opt/homebrew/Cellar/zeek/6.2.1/lib/zeek/python/zeekpkg/template.py", line 566, in instantiate
    for orig_file, path_name, file_name, content in self._walk(tmpl):
  File "/opt/homebrew/Cellar/zeek/6.2.1/lib/zeek/python/zeekpkg/template.py", line 670, in _walk
    out_content = self._replace(tmpl, hdl.read())
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/zeek/6.2.1/lib/zeek/python/zeekpkg/template.py", line 692, in _replace
    val = bytes(val, "ascii")
          ^^^^^^^^^^^^^^^^^^^
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-1: ordinal not in range(128)
error: problem during template instantiation: 'ascii' codec can't encode characters in position 0-1: ordinal not in range(128)

Expected Output:

The package should be created successfully, handling non-ASCII characters in the user inputs without errors.

Environment:

• zkg version: 3.0.1
• Zeek version: 6.2.1
• Python version: 3.12.4
• OS: macOS (using homebrew)

Additional Information:

The issue seems to stem from an attempt to encode non-ASCII characters using the ASCII codec, resulting in a UnicodeEncodeError.

Please consider updating the relevant code to handle non-ASCII characters.