Test: ./updater.sh update --force --branch_and_commit --push_change googletest
Test: aosp/889542
Change-Id: I1025e2ded65000ce34e2f02f84052e7871e425d3

Bug: 109748616
Test: ./updater.sh check kotlinc googletest --json_output=/tmp/res.json
Test: out/soong/host/linux-x86/bin/external_updater_notifier \
          --result_file=/tmp/res.json \
          --history ~/updater/history \
          --recipients=hhb@google.com

Change-Id: I27a4c1c2604d38106a08ce3eee1bcd03fdce80d7

Test: updater.sh update xz-java
Change-Id: I3924b5651f2fac3c5d7493964b570f2f39bc4777

If the upstream is GIT and version is not a hash, updater will try to
list upstream tags to find a newer version. And suggest to merge from
that tag.

Change-Id: I34651815c761c78fd0485df0a84adc086a810e9e
Test: Change googletest/METADATA to follow upstream releases. And run updater.

Add the support to check how far a project is behind upstream git.

Still need to manually run git merge. But this tool can help update
METADATA. :)

Test: ./updater.sh update perf_data_converter
Change-Id: Ic46a0eb723ae22f0fc7d61a67a14299761b564a4