chore(deps): update helm chart common to v8.15.0 (#1859)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

charts/stable/synapse/Chart.yaml

@@ -3,7 +3,7 @@ appVersion: "1.51.0"
 dependencies:
 - name: common
   repository: https://truecharts.org
-  version: 8.14.5
+  version: 8.15.0
 - condition: postgresql.enabled
   name: postgresql
   repository: https://truecharts.org/
@@ -24,7 +24,7 @@ maintainers:
 name: synapse
 sources: []
 type: application
-version: 1.0.3
+version: 1.0.4
 annotations:
   truecharts.org/catagories: |
     - cloud