Update Synapse to 1.138.0

Author: remram44

charts/matrix/Chart.yaml

@@ -4,10 +4,10 @@ description: A chart for Matrix.org, includes Synapse, PostgreSQL, and Element.
 
 type: application
 
-version: 2.8.0
+version: 2.8.1
 
 # The version of Synapse
-appVersion: "1.137.0"
+appVersion: "1.138.0"
 
 dependencies:
   - name: postgresql