updated pull request template (#16572)

* updated pull request template

* updated to 1.17

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,11 @@
 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > Remember to delete this note before submitting your pull request.
 >
-> For pull requests on 1.15 Features: set Milestone to 1.15 and Base Branch to dev-1.15
+> For pull requests on 1.17 Features: set Milestone to 1.17 and Base Branch to dev-1.17
 > 
-> For pull requests on Chinese localization, set Base Branch to release-1.14
+> For pull requests on Chinese localization, set Base Branch to release-1.15
 >
-> For pull requests on Korean Localization: set Base Branch to dev-1.14-ko.\<latest team milestone>
+> For pull requests on Korean Localization: set Base Branch to dev-1.16-ko.\<latest team milestone>
 >
 > If you need Help on editing and submitting pull requests, visit:
 > https://kubernetes.io/docs/contribute/start/#improve-existing-content.