Merge pull request #20999 from Homebrew/cask-signing-audit-message

cask/audit: adjust signing failure error message

Author: MikeMcQuaid

Library/Homebrew/cask/audit.rb

@@ -550,13 +550,20 @@ def audit_signing
           next true if cask.deprecated? && cask.deprecation_reason == :fails_gatekeeper_check
           next true if is_in_skiplist
 
-          add_error <<~EOS, location: url.location
+          signing_failure_message = <<~EOS
             Signature verification failed:
             #{result.merged_output}
-            macOS on ARM requires software to be signed.
-            Please contact the upstream developer to let them know they should sign and notarize their software.
           EOS
 
+          if cask.tap.official?
+            signing_failure_message += <<~EOS
+              The homebrew/cask tap requires all casks to be signed and notarized by Apple.
+              Please contact the upstream developer and ask them to sign and notarize their software.
+            EOS
+          end
+
+          add_error signing_failure_message
+
           true
         end