Minor improvements

[adams85]

Describe the purpose of your pull request

• Implement integration tests for making sure that Unicode characters outside the ASCII range are handled correctly.
• Minor dev env improvements.
• Update to configcat-common v9.1.0.

Related issues (only if applicable)

https://trello.com/c/4gd0Y3EA

Requirement checklist (only if applicable)

• [ ] I have covered the applied changes with automated tests.
• [ ] I have executed the full automated test set against my changes.
• [ ] I have validated my changes against all supported platform versions.
• [ ] I have read and accepted the contribution agreement.

[sonarcloud[bot]]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c40dae7) 90.27% compared to head (f233b3b) 90.27%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #70 +/- ## ======================================= Coverage 90.27% 90.27% ======================================= Files 3 3 Lines 72 72 Branches 10 10 ======================================= Hits 65 65 Misses 7 7 ```

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