feat(devcontainer): add volume mounts for zephyr, modules and tools
This effectively caches Zephyr and its dependencies.  It also shares them between containers.
PR:
},
"mounts": [
"type=volume,source=zmk-root-user,target=/root",
- "type=volume,source=zmk-config,target=/workspaces/zmk-config"
+ "type=volume,source=zmk-config,target=/workspaces/zmk-config",
+ "type=volume,source=zmk-zephyr,target=${containerWorkspaceFolder}/zephyr",
+ "type=volume,source=zmk-zephyr-modules,target=${containerWorkspaceFolder}/modules",
+ "type=volume,source=zmk-zephyr-tools,target=${containerWorkspaceFolder}/tools"
],
"extensions": ["ms-vscode.cpptools"],
"settings": {
