Update GitHub Action workflow files to make use of the reusable pattern

[desrosj]

When Dependabot opens a pull request to update third-party action versions, the PR will always need manual intervention because the template file is not updated and the next run of update.php erases the changes to the .github/workflows directory.

Dependabot does support specifying multiple directories, but it's unclear whether

• a file with invalid YAML (which the template is considered) would be updated correctly.
• a file outside of the .github folder would be updated

If the file must be valid YAML, then the tokens could be changed to be within comments. If the file needs to be inside .github/, perhaps the template could be moved.

[desrosj]

I've looked into this a bit and it's unlikely that Dependabot can be configured to manage the template file. The better approach would be to make use of the reusable workflow pattern here.

The calling workflows containing the matrix strategies should be generated from the template, passing the necessary values to the reusable one, which would contain the references to third-party actions.