Merge branch 'stable-3.1'

* stable-3.1:
  Bump Bazel version to 3.4.1
  Upgrade bazlets to latest stable-2.16

Change-Id: I0a0e57c90b81c97f7a497d18157954a0e8b85c68
diff --git a/.bazelversion b/.bazelversion
index fd2a018..47b322c 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-3.1.0
+3.4.1