[Conformance]: Adds GatewayClass SupportedVersion Test

[danehans]

What type of PR is this?
/kind test
/area conformance

What this PR does / why we need it:
Adds a test to ensure implementations conform to the GatewayClass SupportedVersion status condition.

Which issue(s) this PR fixes:
Fixes #3367

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: danehans
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[youngnick]

The change basically lgtm, but you'll need to remove the "fixes ..." from the commit message @danehans, Prow doesn't let us do that in commit messages.

[danehans]

Commit b40de38 removes "Fixes..." from the commit message. Thanks for the review @youngnick.

[arkodg]

thanks @danehans, does this test pass on any implementations ?

[danehans]

@arkodg thanks for the review. Yes, this PR was tested with solo-io/gloo#10140 for Gloo Gateway:

go test ./conformance -run TestConformance -args \
    --gateway-class=gloo-gateway \
    --supported-features=Gateway \
    --run-test=GatewayClassSupportedVersionCondition
ok  	sigs.k8s.io/gateway-api/conformance	18.789s