Upgrade sliding-sync (v0.99.10 -> v0.99.11)

roles/custom/matrix-sliding-sync/defaults/main.yml

@@ -5,7 +5,7 @@
 
 matrix_sliding_sync_enabled: true
 
-matrix_sliding_sync_version: v0.99.10
+matrix_sliding_sync_version: v0.99.11
 
 matrix_sliding_sync_scheme: https