Promote v1alpha1 `ClusterExtension` API version to v1

[everettraven]

Once all the changes to stabilize the ClusterExtension API have been made, we need to ensure we update the API version from v1alpha1 to v1

Note

This issue should be done as one of the last in the chain

[yashoza19]

/assign

[everettraven]

@yashoza19 Just a heads up that this issue should be the last one done and may be held for a bit pending another round of API review after all planned changes are made to ensure we haven't missed anything.

[yashoza19]

@yashoza19 Just a heads up that this issue should be the last one done and may be held for a bit pending another round of API review after all planned changes are made to ensure we haven't missed anything.

Thanks for the heads up. I figured this issue might not be in progress until all other API ones are done. I'll pick up something else in the meantime.