Add antctl-darwin-arm64 to release assets (#6640)

It was an oversight not to distribute an antctl binary that can run
natively on Apple ARM-based chips.

Note that macOS bundles an emulation solution (Rosetta 2) to enable
x86 applications to run on their ARM-based chips, so `antctl-darwin-x86_64`
can typically be used on these machines. However, it is common practice
for OSS projects to provide a native arm64 binary.

Signed-off-by: Antonin Bas <[email protected]>

hack/release/prepare-assets.sh

@@ -58,6 +58,7 @@ ANTREA_BUILDS=(
     "linux arm linux-arm"
     "windows amd64 windows-x86_64.exe"
     "darwin amd64 darwin-x86_64"
+    "darwin arm64 darwin-arm64"
 )
 
 for build in "${ANTREA_BUILDS[@]}"; do