Don't cache git credentials in workflows

[ncoghlan]

Includes a small update to the launch modules in
the sample project so the PR generation for output updates is tested with the updated workflow.

Addresses initial manual workflow scan for #50

[ncoghlan]

Workflow scan failure is expected, as the scan result upload won't work until the repo has been published (see the usage caveats in https://docs.github.com/en/code-security/code-scanning/integrating-with-code-scanning/uploading-a-sarif-file-to-github ):

  Warning: Advanced Security must be enabled for this repository to use code scanning.
  Error: Advanced Security must be enabled for this repository to use code scanning.
  Warning: Advanced Security must be enabled for this repository to use code scanning.

All the workflow scan steps prior to that ran as expected.