ci: Upload SARIF files with lint results

[nikclayton]

Perform the lint check as normal, saving the exit code and ignoring any
error exit codes.

Then upload the lint results as SARIF files for display in GitHub.

Then exit with whatever exit code lint returned, to ensure that a lint
failure causes the CI job to fail too.

[github-advanced-security]

This pull request sets up GitHub code scanning for this repository. Once the scans have completed and the checks have passed, the analysis results for this pull request branch will appear on this overview. Once you merge this pull request, the 'Security' tab will show more code scanning analysis results (for example, for the default branch). Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results. For more information about GitHub code scanning, check out the documentation.