Update open-policy-agent dependency

[dereknola]

There is currently a dead dependency chain

go mod tidy
go: github.com/Microsoft/hcsshim@v0.11.4 requires
	github.com/open-policy-agent/opa@v0.42.2 requires
	oras.land/oras-go@v1.2.0 requires
	github.com/distribution/distribution/v3@v3.0.0-20221208165359-362910506bc2 requires
	github.com/mitchellh/osext@v0.0.0-20151018003038-5e2d6d41470f: invalid version: git ls-remote -q origin in /home/derek/go/pkg/mod/cache/vcs/94ed57c5b21c953d93b47487113db43a5c9b69fd990329ec70dc77348c4dd443: exit status 128:
	remote: Repository not found.
	fatal: repository 'https://github.com/mitchellh/osext/' not found

Updating open-policy-agent to latest would resolve this error.

[dereknola]

There is currently an open dependabot PR for this #1976