CODEOWNERS: add cockroach_versions.go to upgrade-prs

Recently, a pre-v24.2 gate was merged to master. This would have
probably been avoided if the release/upgrade teams were on the PR.

Epic: none
Release note: None

.github/CODEOWNERS

@@ -416,6 +416,7 @@
 /pkg/ccl/workloadccl/        @cockroachdb/test-eng #! @cockroachdb/sql-foundations-noreview
 /pkg/ccl/benchccl/rttanalysisccl/     @cockroachdb/sql-foundations
 #!/pkg/clusterversion/       @cockroachdb/dev-inf-noreview  @cockroachdb/kv-prs-noreview @cockroachdb/test-eng-prs
+/pkg/clusterversion/cockroach_versions.go @cockroachdb/release-eng-prs @cockroachdb/upgrade-prs
 /pkg/cmd/allocsim/           @cockroachdb/kv-prs
 /pkg/cmd/bazci/              @cockroachdb/dev-inf
 /pkg/cmd/cloudupload/        @cockroachdb/dev-inf