Merge branch 'docs-apiv3-removal-msg' into 'master'

Make API v3 removal date more clear/match blog post

See merge request !11482

doc/api/v3_to_v4.md

@@ -2,7 +2,9 @@
 Since GitLab 9.0, API V4 is the preferred version to be used.
-V3 will remain working until at least GitLab 9.3. The V3 API documentation is still [available](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-16-stable/doc/api/README.md).
+API V3 will be removed in GitLab 9.5, to be released on August 22, 2017. In the 
+meantime, we advise you to make any necessary changes to applications that use 
+V3. The V3 API documentation is still [available](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-16-stable/doc/api/README.md).
 Below are the changes made between V3 and V4.