Decide on versioning and installation

[ja-he]

a couple of orthogonal goals need to be weighed against each other here

• i like the simplicity of go install github.com/ja-he/dayplan@latest
  • conversely wouldn't love shipping a separate install script/Makefile/...
• imo a version subcommand (or --version/-v) is necessary
  • right now this is implemented as baked into the source
    • adds noise either in the form of extra commit contents unrelated to commit message or in the form of extra versioning commits
    • some incompetent might forget to update it
  • go allows you to do this with ldflags, so you might change a few int variables major, minor, patch when you build; obviously getting the values from git tags isn't an issue there either;
    • this annoys me because it complicates the build/install command

So I'd like to say "just go install this thing" and also have a no-extra-effort version subcommand that returns something like v1.2.3 (commit: deadbeef); but these goals seem to conflict. What to do?