Modify postCreateCommand as a test

Author: hubwriter

.devcontainer/test-custom-devcontainer/devcontainer.json

@@ -34,7 +34,8 @@
 	"forwardPorts": [4000],
 
 	// Use 'postCreateCommand' to run commands after the container is created.
-	"postCreateCommand": "git lfs pull && npm ci",
+	//"postCreateCommand": "git lfs pull && npm ci",
+	"postCreateCommand": "echo This file was created by the postCreateCommand in the custom devcontainer.json > aaa-TEST.txt",
 
 	// Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
 	"remoteUser": "node"