change exntension yml to yaml

docker/joplin-server/with-db/compose.yaml

@@ -0,0 +1,8 @@
+# Docker Compose v2.20 or greater required to use "include"
+include:
+#################### NETWORKS ####################
+  - ../../compose/networks/proxy.yaml
+  - ../../compose/networks/socket-proxy.yaml
+#################### SERVICES ####################
+  - ../../compose/postgres.yaml
+  - ../../compose/joplin-server.yaml