chore: Use pnpm@8.8.0 on DevContainer (#11975)

.devcontainer/devcontainer.json

@@ -4,7 +4,9 @@
 	"service": "app",
 	"workspaceFolder": "/workspace",
 	"features": {
-		"ghcr.io/devcontainers-contrib/features/pnpm:2": {},
+		"ghcr.io/devcontainers-contrib/features/pnpm:2": {
+			"version": "8.8.0"
+		},
 		"ghcr.io/devcontainers/features/node:1": {
 			"version": "20.5.1"
 		}