feat(Series) - Added `items()` method

[mobley-trent]

• [ ] Sub task of #1259
• [x] Tests added / passed
• [x] Passes pre-commit run --all-files

[GPUtester]

Can one of the admins verify this patch?

Admins can comment ok to test to allow this one PR to run or add to allowlist to allow all future PRs from the same author to run.

[github-actions[bot]]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

     15 files  ± 0       15 suites  ±0   3h 17m 13s :stopwatch: + 1m 44s  13 032 tests + 1   12 100 :white_check_mark:  - 1     931 :zzz: + 1  1 :x: +1  161 164 runs  +12  144 627 :white_check_mark:  - 5  16 536 :zzz: +16  1 :x: +1 

For more details on these failures, see this check.

Results for commit 557b6918. ± Comparison against base commit ba5f3bc9.

This pull request removes 2 and adds 3 tests. Note that renamed tests count towards both.

dask.tests.test_tokenize ‑ test_tokenize_local_classes_from_different_contexts
dask.tests.test_tokenize ‑ test_tokenize_local_instances_from_different_contexts

dask.dataframe.tests.test_dataframe ‑ test_items
dask.tests.test_tokenize ‑ test_tokenize_local_classes_from_different_contexts[False]
dask.tests.test_tokenize ‑ test_tokenize_local_classes_from_different_contexts[True]

This pull request removes 1 skipped test and adds 2 skipped tests. Note that renamed tests count towards both.

dask.tests.test_tokenize ‑ test_tokenize_local_instances_from_different_contexts

dask.tests.test_tokenize ‑ test_tokenize_local_classes_from_different_contexts[False]
dask.tests.test_tokenize ‑ test_tokenize_local_classes_from_different_contexts[True]