Update asonix/pictrs Docker tag to v0.5.16 (#4813)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

docker/docker-compose.yml

@@ -75,7 +75,7 @@ services:
     init: true
 
   pictrs:
-    image: asonix/pictrs:0.5.14
+    image: asonix/pictrs:0.5.16
     # this needs to match the pictrs url in lemmy.hjson
     hostname: pictrs
     # we can set options to pictrs like this, here we set max. image size and forced format for conversion

docker/federation/docker-compose.yml

@@ -49,7 +49,7 @@ services:
 
   pictrs:
     restart: always
-    image: asonix/pictrs:0.5.14
+    image: asonix/pictrs:0.5.16
     user: 991:991
     volumes:
       - ./volumes/pictrs_alpha:/mnt:Z