Automatically upload SARIF report to Github

A user can currently upload the generated SARIF report by adding an additional step in their workflow using the [upload-sarif](https://github.com/github/codeql-action/tree/main/upload-sarif) action from `codeql-action`. It might be nice if this happens automatically when using the `scan-action`. It looks like there [has been some movement on composite actions](https://github.com/actions/runner/pull/612#issuecomment-895201453), this might make adding the `upload-sarif` step trivial. [Or maybe it's been implemented finally?](https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#runsstepsuses)

**NOTE: this is likely to require adding `partialFingerprints` to the SARIF output**

Start with the scan-action workflow or action definition and the upload-sarif and composite-action documentation linked in the issue. Check whether automatic SARIF upload is supported and whether the generated report includes partialFingerprints; done means the report uploads without an additional workflow step.

Written by the indexing model from the issue text.