strongbox release script

These scripts help automate the release process for strongbox.

prep.sh

Prepares a release branch of strongbox for review.

1. create a release branch.
2. update references to static version numbers in the project.clj, readme.md, security.md, etc
3. updates the changelog, changing references to 'unreleased'
4. regenerates the pom.xml file
5. commits it all, pushes to release branch and opens a PR for review with a checklist of things to do.

release.sh

Assumes prep.sh has been run, the changes reviewed and the PR merged into master.

1. tags the release
2. creates a GitHub release from the new tag
3. generates an AppImage
4. uploads the artifacts to the Github release
5. updates the Arch AUR
6. updates Flathub

post.sh

Switches back to develop, merges changes from master, truncates TODO, updates project file, etc etc.