adds missing compose for oauth2 proxy

docker_compose_applications/oauth2-proxy/compose.yaml

@@ -0,0 +1,15 @@
+services:
+  oauth2-proxy:
+    image: quay.io/oauth2-proxy/oauth2-proxy:latest
+    container_name: oauth2-proxy
+    restart: unless-stopped
+    command:
+      - --config=/etc/oauth2-proxy/oauth2-proxy.cfg
+    volumes:
+      - ./oauth2-proxy.cfg:/etc/oauth2-proxy/oauth2-proxy.cfg:ro
+    networks:
+      - caddy_net
+
+networks:
+  caddy_net:
+    external: true