Apply multi-arch hints.

+ ruby-android-key-attestation: Add Multi-Arch: foreign.

Changes-By: apply-multiarch-hints

debian/control

@@ -21,6 +21,7 @@ XB-Ruby-Versions: ${ruby:Versions}
 Depends: ${misc:Depends},
          ${ruby:Depends},
          ${shlibs:Depends}
+Multi-Arch: foreign
 Description: Android key attestation verification
  A Ruby gem to verify Android Key attestation statements on your server. Key
  attestation allows you to verify that the cryptographic keys you use in apps