ticket:10445: tag release 52.1

git-svn-id: http://source.icu-project.org/repos/icu/icu@34523 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10461: Create branch.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34524 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10461: Remove branch.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34525 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10461: Create branch.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34526 251d0590-4201-4cf1-90de-194747b24ca1