Release v0.12.4
Start v0.12.5-dev
Add guards to lstrip and rstrip
Emit warnings for using % as sigils
Automatically recompile on outdated elixir version
`mix deps.get` does not use MIX_ENV
Revert "`mix deps.get` does not use MIX_ENV"

This reverts commit 1e9cd551ce6fe2406e4b664a67faa8660d722201.