Generate conformance report for NKG at each release

[mpstefan]

At each release, a conformance report is generated and published of the NKG release.

Acceptance

• When a new release is created for NKG, the conformance report is generated automatically and published as an artifact alongside our release.

[sjberman]

See this commit for how to generate the report.

[kate-osborn]

Also, see the last generated report: https://github.com/kubernetes-sigs/gateway-api/blob/main/conformance/reports/v0.7.1/nginxinc-nginx-kubernetes-gateway.yaml

Some fields, like the summaries, have to be added manually. We decided to set the contact field to the new issue link instead of @nginxinc/kubernetes-gateway.

[sjberman]

Waiting for 0.8.0 release that includes some needed bug fixes.