Merge branch 'stable-3.1'

* stable-3.1:
  Upgrade bazlets to latest stable-3.1 to build with 3.1.8 API
  Upgrade bazlets to latest stable-3.0 to build with 3.0.12 API
  Upgrade bazlets to latest stable-2.16 to build with 2.16.22 API
  Bump Bazel version to 3.4.1

Change-Id: I86098f5a079d9fa9e4a2418bce51b0466c6b1563
diff --git a/.bazelversion b/.bazelversion
index fd2a018..47b322c 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-3.1.0
+3.4.1