Bump Bazel version to 3.0.0

Change-Id: I3866b58d3d288f37b1818be5b56d05e8be6ecb0f
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

.bazelversion

diff --git a/.bazelversion b/.bazelversion
index ccbccc3..4a36342 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-2.2.0
+3.0.0