This restores compatibility with go1.18, which was broken since commit;
c062238ea4
cmd.Environ() is new in go1.19, and not needed for this specific case.
Without this, trying to use this package in code that uses go1.18 will fail;
builder/remotecontext/git/gitutils.go:216:23: cmd.Environ undefined (type *exec.Cmd has no field or method Environ)
Changing to use `os.Environ()` instead restores compatibility with go1.18
Full diff: f9cb47a052...5aac513617
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
67e6ba0d09