chore(workflows/tests): remove php 8.1 test

[ygnice]

Your checklist for this pull request

🚨Please review the guidelines for contributing to this repository.

What kind of change does this PR introduce？ (check at least one)

• Bugfix
• Feature
• Docs update
• Code style update
• Refactor
• Performance Improvements
• Build-related changes
• Other, please describe:

Does this PR introduce a BREAKING CHANGE? (check one)

• Yes
• No

The PR fulfills these requirements:

• Make sure you are requesting to pull a feature/bugfix branch (right side). Don't request master!
• Make sure you are making a pull request against the develop branch (left side). Also you should start your branch off our develop branch.
• Check the commit's or even all commits' message styles matches our requested structure.
• Check your code additions will fail neither code linting checks nor unit test.
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Description

Please describe your pull request.

❤️ Thank you!

[codecov]

Codecov Report

Merging #8 (7d9afe7) into main (ead6776) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main       #8   +/-   ##
=========================================
  Coverage     61.01%   61.01%           
  Complexity       18       18           
=========================================
  Files             4        4           
  Lines            59       59           
=========================================
  Hits             36       36           
  Misses           23       23