Pin dependencies

Author: renovate[bot]

.devcontainer/docker-compose.yml

@@ -2,7 +2,7 @@ version: '3.6'
 
 services:
   app:
-    image: wordpress
+    image: wordpress@sha256:2c739b2bbaeb48697400ac19f9d3da52628b0516368c22ece36e1c39f081c533
     restart: always
     ports:
       - 8080:80
@@ -15,7 +15,7 @@ services:
       - ../..:/workspaces:cached
 
   db:
-    image: mariadb
+    image: mariadb@sha256:65c0c44bc4754bd03dc17396328f2adae8f156ebe6ec1edb928386886654785e
     restart: unless-stopped
     environment:
       MYSQL_DATABASE: exampledb