PROJQUAY-7741 Bump go-version to 1.21 for quay-operator
quay/quay-operator#944: chore: Bump go version to 1.21 (PROJQUAY-7722)
quay/quay-operator#947: [redhat-3.11] chore: Bump go version to 1.21 (PROJQUAY-7722)
quay/quay-operator#948: [redhat-3.12] chore: Bump go version to 1.21 (PROJQUAY-7722)