Add branch+commit to "What to Test" field in TestFlight. (#360)

fastlane/Fastfile

@@ -126,6 +126,7 @@ platform :ios do
       skip_submission: false,
       ipa: "iAPS.ipa",
       skip_waiting_for_build_processing: true,
+      changelog: git_branch+" "+last_git_commit[:abbreviated_commit_hash],
     )
   end