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

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

Test: NA
Change-Id: If5d8d0ea5903e1cf4c2cb62dd3802fb3706458cb

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.

As an example, if there is commit C (300 days old) in dev branch. Later dev is merged into upstream-master as commit M (2 days old).

Before this change, the updater will say "2 commits (300 days) behind" because both C and M is not in master.

After this change, it will say "1 commit (2 days) behind", which makes more sense.

(This change raises error when there's no merge base between upstream and master. But I think it is expected)

Test: updater.sh check googletest
Change-Id: I963b378e61677c1f6ea13af0d0f558846040b840

This change computes edit distant between old url and each of new urls.
And use the url most like previous one.

Test: update any library
Change-Id: I959a22168652c7543da2cdb29d36a1d061ade7e9

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