update to Gateway API v0.7.1

[skriss]

Once Gateway API v0.7.0 release is out, we should upgrade.

Gateway API v0.7.0-rc1 is out: https://github.com/kubernetes-sigs/gateway-api/releases/tag/v0.7.0-rc1

Work can be started to upgrade and identify any changes that need to be addressed.

[sunjayBhatia]

Updated title to reflect we're bumping to v0.7.1 for posterity

[sunjayBhatia]

Release link: https://github.com/kubernetes-sigs/gateway-api/releases/tag/v0.7.1