Updates our MSRV to 1.56, which is coming up on 3 years old as of this PR.
Fixing CI because macos-latest now runs on ARM64 instead of x86.
Applies a small fix to the environment variable reading on UNIX platforms so variables without contents are skipped and don't hinder reading from ones that may.
This PR handles
twothree things:macos-latest
now runs on ARM64 instead of x86.Closes #28