Add support for arm64v8 architecture.

Signed-off-by: Odidev <[email protected]>

library/znc

@@ -1,7 +1,7 @@
 Maintainers: Alexey Sokolov <[email protected]> (@DarthGandalf)
 GitRepo: https://github.com/znc/znc-docker.git
 GitCommit: 39116f34fa92cb9c9b170c60bfb32411d408a582
-Architectures: amd64, arm32v6
+Architectures: amd64, arm32v6, arm64v8
 
 Tags: 1.7.0, 1.7, latest
 Directory: full