[nats] Fix arch for arm64 and add sha verification

Signed-off-by: Ivan Kozlovic <[email protected]>

library/nats

@@ -3,7 +3,7 @@ Maintainers: Derek Collison <[email protected]> (@derekcollison),
              Waldemar Salinas <[email protected]> (@wallyqs),
              Jaime Piña <[email protected]> (@variadico)
 GitRepo: https://github.com/nats-io/nats-docker.git
-GitCommit: a24499a62a425656d693954cd507ff3360f7cb32
+GitCommit: 936765ff17c10ab99f0141962897a93914b7e64d
 
 Tags: 2.1.7-alpine3.11, 2.1-alpine3.11, 2-alpine3.11, alpine3.11, 2.1.7-alpine, 2.1-alpine, 2-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8