Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  Bump required Bazel version to 2.1.0

Change-Id: I1770e3a2301d067d3ee20a01ac7da7bf1cf63167
diff --git a/.bazelversion b/.bazelversion
index 227cea2..7ec1d6d 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-2.0.0
+2.1.0