Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Bump required Bazel version to 2.1.0

Change-Id: Id2baed443dc1e37c26dd6f714beb92184812791a

.bazelversion

diff --git a/.bazelversion b/.bazelversion
index 227cea2..7ec1d6d 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-2.0.0
+2.1.0