Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14

Change-Id: I3eae342cdad7494df4b39c2e7c28a40258798906
diff --git a/.bazelversion b/.bazelversion
new file mode 100644
index 0000000..09d1d01
--- /dev/null
+++ b/.bazelversion
@@ -0,0 +1,2 @@
+0.29.0
+