Remove dependency on github.com/golang/glog

[jdolitsky]

Please see sigstore/policy-controller#112 for more context.

TLDR - without this being removed, policy-controller will crash on startup due to conflicts with the klog dependency.

This appears to be brought in via github.com/google/certificate-transparency-go. After looking there, it led to a rabbit hole of other dependencies which also rely on glog.

I've opened up the following PRs which may or may not be all of the locations:

• Switch from glog to klog google/certificate-transparency-go#962
• Switch from glog to klog google/trillian#2787
• Switch from glog to klog google/go-licenses#138
• Switch from glog to klog grpc/grpc-go#5547

An alternative could be for the sigstore org to maintain a fork of glog, just for replace purposes. The required changeset would be this.

[haydentherapper]

For some context, I tried to work around this issue awhile ago by copying in files from certificate-transparency-go (https://github.com/sigstore/cosign/blob/f2c360eb97e52fa7766ecde370f1a48b910d7404/cmd/cosign/cli/fulcio/fulcioverifier/ctutil/ctutil.go) to avoid pulling in glog.

[haydentherapper]

Seems to be resolved, I don't see a dependency on glog anymore