* Add linux/arm64 support to bazel rules
* Make linux arm64 sha optional and PR feedback
Not all releases have linux shas. Use getattr to default to no sha if none was
present. This way non linux arm64 builds should not fail.
* Update linux arm64 sha for 3.1.33
This is the latest arm64 release according to #1204. There do not seem to be a any releases between .21 and .33.