Bump bazel version to 4.0.0

Change-Id: I2faa67d5083f23b29f7a434e54c5e17360b1c0fe
Signed-off-by: David Ostrovsky <david@ostrovsky.org>
diff --git a/.bazelversion b/.bazelversion
index 8faff82..fcdb2e1 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-4.0.0rc2
+4.0.0