Bump Bazel version to 3.5.0

This latest release includes cherry picks, a new feature and some
important changes [1].

[1] https://github.com/bazelbuild/bazel/releases/tag/3.5.0

Change-Id: Ie6966b0b56a351f98cb20b25daf3412740e68562
Signed-off-by: Marco Miller <marco.miller@ericsson.com>

.bazelversion

@@ -1 +1 @@
-3.1.0
+3.5.0