Bump Bazel version to 2.0.0

Change-Id: Ia68a38c19982b8c03ec0df5effef1e6b8b5591e3
diff --git a/.bazelversion b/.bazelversion
index 9084fa2..227cea2 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-1.1.0
+2.0.0