release: unify versioning, add previousRelease and upcomingRelease

Created by: bobheadxi

• Replaces majorVersion, minorVersion in configuration with previousRelease and upcomingRelease
  • This is required for https://github.com/sourcegraph/sourcegraph/issues/15074 , where some of the formatting depends on what the previous release was (e.g. headers with RELEASE_A -> RELEASE_B). Opens potential for other types of automation as well.
• Removes all version arguments - versions are already defined in config so there should be no need to have this defined as arguments as well. Simplifies release template.

Updated release process: https://github.com/sourcegraph/about/pull/1880

Created by: bobheadxi

@pecigonzalo in response to your feedback that it is nice to be explicit on the command line, but still keeping the overall reduced verbosity + reduced sources of configuration, I added a confirmation prompt in 5ed2874202f386d5cd2981fb5e70137e75867c7f that will prompt for a confirmation of the current release that is cached for the week:

❯ yarn run release tracking:release-issue
yarn run v1.22.4
$ node ./out/release.js tracking:release-issue
Please confirm the upcoming release version: 3.22.0

Hope that resolves your concern!