add repo-dispatch action with test

[dennisvang]

Added a repo-dispatch action that triggers a repository_dispatch event in another repository via the github API.

This requires a personal access token with "Contents" write permission for the target repository, in the secret-token variable.

See api docs.

Usage example:

jobs:
e2e:
needs: publishruns-on: ubuntu-lateststeps:
- name: trigger e2e testsuses: FAIRDataTeam/github-workflows/.github/actions/repo-dispatch@v3with:
secret-token: ${{ secrets.MY_REPO_DISPATCH_TOKEN }}target-repo-name: FAIRDataPoint-E2E-Teststarget-repo-owner: FAIRDataTeamevent-type: trigger-testsclient-payload: | { "fdp_version": "${{ github.ref_name }}", "fdp_client_version": "latest" }

fixes#14