* stable-5.2: Prepare 5.1.17-SNAPSHOT builds JGit v5.1.16.202106041830-r BatchRefUpdate: Skip saving conflicting ref names and prefixes in memory BatchRefUpdateTest: Accurately assert RefsChangedEvent(s) fired Optimize RefDirectory.isNameConflicting() Update bazlets and bazel version Change-Id: I7838f7d237a3598bf55995426d7ba1de146cb6ad