mastodon: bump to 4.0.6

Fixes after the security bugfix last week.
Not yet rolled out to qa/prod.

Change-Id: I52de0dc1d082fd1c6269025b1f41d87c02c67113
Reviewed-on: https://gerrit.hackerspace.pl/c/hscloud/+/1536
Reviewed-by: q3k <q3k@hackerspace.pl>
diff --git a/app/mastodon/kube/mastodon.libsonnet b/app/mastodon/kube/mastodon.libsonnet
index 826f6fc..6261323 100644
--- a/app/mastodon/kube/mastodon.libsonnet
+++ b/app/mastodon/kube/mastodon.libsonnet
@@ -15,7 +15,7 @@
         # /.well-known/webfinger to webDomain.
         webDomain: cfg.localDomain,
         images: {
-            mastodon: "tootsuite/mastodon:v4.0.5@sha256:472c355da5a27b91005dc78c0b5cf75d6baaf1c561c29db1c49ce9168c5de0a9",
+            mastodon: "tootsuite/mastodon:v4.0.6@sha256:472c355da5a27b91005dc78c0b5cf75d6baaf1c561c29db1c49ce9168c5de0a9",
         },
         passwords: {
             # generate however you like