disable building of appimage on release

appimage testing is currently broken due to a requirement to have access
to /dev/snd, which is not present on the image we are using in circleci.

.circleci/config.yml

@@ -976,19 +976,10 @@ workflows:
             tags:
               only:
                 - /^v\d+\.\d+\.\d+(-rc\d+)?$/
-      - build-appimage:
-          filters:
-            branches:
-              ignore:
-                - /.*/
-            tags:
-              only:
-                - /^v\d+\.\d+\.\d+(-rc\d+)?$/
       - publish:
           requires:
             - build-all
             - build-macos
-            - build-appimage
           filters:
             branches:
               ignore: