temporary fix for mastodon cache

ansible/roles/mastodon/docker-stack.yml.j2

@@ -7,7 +7,6 @@ networks:
   mastodon:
 
 volumes:
-  cache:
   system:
     driver_opts:
       type: "nfs"
@@ -83,7 +82,9 @@ services:
         target: /mastodon/public/system
         volume:
           nocopy: true
-      - cache:/mastodon/public/system/cache
+      - type: bind
+        source: /media/mastodon_cache
+        target: /mastodon/public/system/cache
     deploy:
       placement:
         constraints:
@@ -146,7 +147,9 @@ services:
         target: /mastodon/public/system
         volume:
           nocopy: true
-      - cache:/mastodon/public/system/cache
+      - type: bind
+        source: /media/mastodon_cache
+        target: /mastodon/public/system/cache
     healthcheck:
       test: ['CMD-SHELL', "ps aux | grep '[s]idekiq\ 6' || false"]
     deploy: