Merge branch 'master' into stable-5.1

* master:
  UploadPackTest: Avoid unnecessarily boxing int into Integer
  Parse signature of GPG-signed commits
  Deprecate Constants.CHARSET in favor of StandardCharsets.UTF_8
  Simplify file creation in ResetCommandTest
  Specify charset when constructing InputStreamReader
  Update Orbit to S20180829155938 for 2018-09 RC1
  Replace useminimalnegotation flag with maxhaves flag
  Extract protocol v2 fetch request parsing to its own class
  FetchV2Request: Rename shallowSince to deepenSince
  FetchV2Request: Correct typo in parameter name
  FetchV2Request round up (doneReceived, renamings)
  Use right variable in error message about depth
  UploadPack: avoid conflating shallow commit lists in protocol v2
  Bazel: Use hyphen instead of underscore in external repository names
  Format BUILD files with buildifier 0.15.0
  Upgrade maven-compiler-plugin to 3.8.0

Change-Id: Ibc6feb828e4ff20a3158e6b75dcfce7617e00b0e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>