Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.18 API
  Bump Bazel version to 3.1.0
  Bump Bazel version to 3.0.0
  Upgrade bazlets to latest stable-2.16 to build with 2.16.17 API
  Upgrade bazlets to latest stable-3.0 to build with 3.0.8 API
  Upgrade bazlets to latest stable-3.0
  Upgrade bazlets to latest stable-2.16
  Bump Bazel version to 2.2.0

Change-Id: Ib792cfb1518f103d8599ac81439a58509ec081c1

.bazelversion

diff --git a/.bazelversion b/.bazelversion
index 7ec1d6d..fd2a018 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-2.1.0
+3.1.0