[CI] Prevented Running the CI If Only the Documentation Is Updated

[ueqri]

Solved https://github.com/verilog-to-routing/vtr-verilog-to-routing/issues/2598.

Added a path-ignore filter to the GitHub Actions triggers (including push and pull_request) to filter out any push or pull request that only includes docs updates.

The "Test" and "Containers" workflows will be skipped if a push or a PR only contains changes to the documentation, such as the developer guide and README, so that we can save CI resources for other uses.

For more details, please refer to the issue page :)

[ueqri]

Another PR for https://github.com/verilog-to-routing/vtr-verilog-to-routing/issues/2545 will be opened as a test case (to verify that this CI change works) after this PR is merged.

[vaughnbetz]

Will CI still build the documentation? That is useful ... you can ensure read the docs builds and look at the rendered/built documentation in advance of merging the PR. I agree other tests are not useful in that case, but the read the docs build should be preserved.

[ueqri]

Will CI still build the documentation?

Yes. The online documentation build is relying on the Read the Docs CI currently, automatically triggered based on the .readthedocs.yaml. The Read the Docs CI is independent from GitHub Actions CI, and will as usual be triggered whenever there is a push to the master branch. Therefore, skipping all the current GitHub CI workflows won't affect the current online documentation build.

[vaughnbetz]

Great, thanks!