install packagers after container creation

Author: ultram4rine

.devcontainer/devcontainer.json

@@ -53,7 +53,7 @@
   // "forwardPorts": [],
 
   // Use 'postCreateCommand' to run commands after the container is created.
-  // "postCreateCommand": "rustc --version",
+  "postCreateCommand": "cargo install cargo-deb cargo-generate-rpm",
 
   // Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
   "remoteUser": "vscode",