Perform submodule init after start

.devcontainer/devcontainer.json

@@ -0,0 +1,19 @@
+{
+  "name": "N64Recomp",
+  "image": "mcr.microsoft.com/devcontainers/cpp:1-ubuntu-22.04",
+
+  // Features to add to the dev container. More info: https://containers.dev/features.
+  // "features": {},
+
+  // Use 'forwardPorts' to make a list of ports inside the container available locally.
+  // "forwardPorts": [],
+
+  // Use 'postCreateCommand' to run commands after the container is created.
+  "postCreateCommand": "git submodule update --init --recursive",
+
+  // Configure tool-specific properties.
+  // "customizations": {},
+
+  // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+  // "remoteUser": "root"
+}