Update Slack link to use slack.bazel.build

PiperOrigin-RevId: 253354235
Change-Id: I9006e6ab21dbe26340a6fc0ee8202474c6282bd8
diff --git a/README.md b/README.md
index 5c16ead..fcd14f6 100644
--- a/README.md
+++ b/README.md
@@ -60,4 +60,4 @@
 
 * [Stack Overflow](https://stackoverflow.com/questions/tagged/bazel)
 * [rules_cc mailing list](https://groups.google.com/forum/#!forum/cc-bazel-discuss)
-* Slack channel `#cc` on [bazelbuild.slack.com](https://bazelbuild.slack.com) (use [bazel-slackin](https://bazel-slackin.herokuapp.com) to join).
+* Slack channel `#cc` on [slack.bazel.build](https://slack.bazel.build)