use root docker-compose.yml for vscode

Motivation is recent versions of docker no longer consider
.devcontainer/docker-compose.yml valid, so vscode can't start the
container.
Solution here is just removing the specific vscode docker-compose.yml
so only the root one is used. There is nothing specific needed in
the vscode specific one anyway.

.devcontainer/devcontainer.json

@@ -7,12 +7,9 @@
 	// Update the 'dockerComposeFile' list if you have more compose files or use different names.
 	// The .devcontainer/docker-compose.yml file contains any overrides you need/want to make.
 	"dockerComposeFile": [
-		"../docker-compose.yml",
-		"docker-compose.yml"
+		"../docker-compose.yml"
 	],
 
-	// The 'service' property is the name of the service for the container that VS Code should
-	// use. Update this value and .devcontainer/docker-compose.yml to the real service name.
 	"service": "onesignal-web-sdk-dev",
 
 	// The optional 'workspaceFolder' property is the path VS Code should open by default when