feature: Add version command.

[betterengineering]

Overview

This change adds pixlet version to be able to determine which version of pixlet you are running 🎉 . Locally, this will default to a git commit. Our released versions will use the git tag, ex v0.17.1.

Considerations

I made sure this works locally, but I have no idea if the piping for the build system will work as expected. I also have no way to test on Windows:

make build && ./pixlet version
rm -f pixlet
rm -rf ./build
rm -rf ./out
go build -ldflags="-X 'tidbyt.dev/pixlet/cmd.Version=f61493c9c3cfbd3b4cd7809bbd08fff008e49c79'" -o pixlet tidbyt.dev/pixlet
Pixlet version: f61493c9c3cfbd3b4cd7809bbd08fff008e49c79

Changes

• feature: Add version command.
  • This commit adds a version command so that folks know what version of pixlet they are currently using.

[betterengineering]

Closes #191