GCR orb missing OIDC support

Hey CircleCI team,

The official GCR orb currently only supports the gcp-cli/setup command using a service account key – there is no way to set use_oidc: true to authenticate using OIDC. There’s an open pull request (#69) to add OIDC support.

Can we get someone from the orbs team to take a look at this PR and merge it? It’s preventing us (and, I suspect, many others) from using this orb.