Pin dependencies

Author: renovate[bot]

.devcontainer/docker-compose.yml

@@ -2,7 +2,7 @@ version: '3.6'
 
 services:
   app:
-    image: wordpress
+    image: wordpress@sha256:c5f075fe71c9120e769edbf761bcf20bf0b73d72d49dfde042a06aafcdfef08d
     restart: always
     ports:
       - 8080:80
@@ -15,7 +15,7 @@ services:
       - ../..:/workspaces:cached
 
   db:
-    image: mariadb
+    image: mariadb@sha256:b30cc65b57a11a2e791ad5c06284e599fe9f1bf3fe9081a88d85bcf36389be4a
     restart: unless-stopped
     environment:
       MYSQL_DATABASE: exampledb