Update to newer briar-headless.jar

Based on current master + clikt 1.7.0

app.briar.gtk.json

@@ -57,8 +57,8 @@
             "sources": [
                 {
                     "type" : "file",
-                    "url" : "https://media.dorfbrunnen.eu/briar/briar-headless.jar",
-                    "sha256": "d4d610ebdc9822f05ade455487921d0eb21469c23ae162fe63da1f557008d586"
+                    "url" : "https://media.dorfbrunnen.eu/briar/patched/briar-headless.jar",
+                    "sha256": "a2b8f35cc55a3bf374d0f7666e852b556404146984893a0a694a457c296846be"
                 }
             ]
         },