Bump bazel version to 1.2.0

Change-Id: Ie42513bd4b2831b7487413b954128a7503cb2958
diff --git a/.bazelversion b/.bazelversion
index 3eefcb9..26aaba0 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-1.0.0
+1.2.0