Force exact match on .get()

[13MK3]

Pull Request Checklist

Thank you for taking the time to improve Arrow! Before submitting your pull request, please check all appropriate boxes:

• [x] 🧪 Added tests for changed code.
• [x] 🛠️ All tests pass when run locally (run tox or make test to find out!).
• [x] 🧹 All linting checks pass when run locally (run tox -e lint or make lint to find out!).
• [ ] 📚 Updated documentation for changed code.
• [x] ⏩ Code is up-to-date with the master branch.

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Description of Changes

These changes were made in collaboration with @khanm3

• Modified the _ONE_OR_TWO_DIGIT_RE regex to not accept numbers with leading zeros. This is done in order to conform to the expected behavior and throw an error when, for example, you try to match '01' with 'M'. The issue #1084 only mentions the 'M' token, but realized that the 'D', 'H', 'm', 'h', and 's' have similar behavior which we have also corrected.
• Modified an existing test case since this test was using the undesired behavior which this pull request is intended to fix
• Added a test case which checks the expected behavior for all 6 tokens.

Closes: #1084

Questions:

• We also noticed that the 'DDD' token seems to have similar behavior as well. If you try to match '001' to 'DDD', should that also be expected to fail? We left that one untouched since it uses a different regex and we weren't positive.
• Unrelated to this pull request, but we noticed that tests/test_arrow.py::TestArrowHumanize::test_months is marked as expected to fail, but before we made any changes, it was already passing. Maybe this should be updated?

[codecov[bot]]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage :thumbsup:

Coverage data is based on head (9cfff58) compared to base (74a759b). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1142 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 9 9 Lines 2319 2319 Branches 492 492 ========================================= Hits 2319 2319 ``` | [Impacted Files](https://codecov.io/gh/arrow-py/arrow/pull/1142?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py) | Coverage Δ | | |---|---|---| | [arrow/parser.py](https://codecov.io/gh/arrow-py/arrow/pull/1142/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py#diff-YXJyb3cvcGFyc2VyLnB5) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=arrow-py)

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[rodrigondec]

This PR is awaiting what? :cry: