Potential fix for https://github.com/DevCycleHQ/assemblyscript-regex/security/code-scanning/2

To fix the issue, explicitly set the permissions required for the workflow, ideally at the root level to ensure all jobs inherit the restriction. Since this workflow only checks out the code and runs tests, no write access is necessary, so the minimal required permissions are contents: read. To implement this, add a permissions block near the top of the file, preferably just after the name key and before the on key, as shown in the best practices examples. No new methods, definitions, or imports are required.

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