pre-release workflow on PR merge doesn't work with forks

[schandrika]

pre-release workflow on PR merge doesn't work when the PR is from a forked repository. This is because only default GITHUB_TOKENs with read access are available when PR is from a fork. other tokens are available only when the PR is from a branch on the repository.
See github issue

[schandrika]

passing of token (GITHUB_TOKEN with write permissions or organization owned personal access token) do not work when the workflow is run "on PR merge" when the PR is from a fork. This is true whether we have code the core logic of the workflow as part of a reusable workflow or duplicated explicitly into individual repository workflow.

Proposed solution:

1. Create a deploy-pre-release workflow in each repository that runs NOT on PR merge but periodically every Friday or when triggered manually. individual repo workflows should call the reusable github-tooling repository's workflow
2. deploy-pre-release workflow on github-tooling repository should do a git diff between develop branch of the caller and the last released tag and if the tag contains files other than *.md and *.rst files (i.e. changes other than documentation) then bump the version in toml file and push a pre-release version to pypi