Use build config with variables for both local and CI builds

[jamezrin]

The idea is to have a file (notion-repackaged.env or notion-repackaged.sh) that has variables for things like the version and the revision, the upstream hash, notion-enhancer commit hash, etc.

This file should be used by the local build script and the CI pipeline. And the github actions workflow should only be triggered when a modification of this file is pushed to the repository https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#onpushpull_requestpaths