{
  "version": "2.0.0",
  "command": "npm",
  "tasks": [{
    "label": "vscode-build",
    "type": "shell",
    "command": "npm",
    "args": ["run", "problems"],
    "group": {
      "kind": "build",
      "isDefault": true
    },
    "problemMatcher": "$tsc",
    "presentation": {
      "echo": true,
      "reveal": "always",
      "focus": false,
      "panel": "shared"
    }
  }]
}

{
  "version": "2.0.0",
  "tasks": [{
    "label": "vscode-build",
    "type": "shell",
    "command": "yarn",
    "args": ["run", "problems"],
    "group": {
      "kind": "build",
      "isDefault": true
    },
    "problemMatcher": "$tsc",
    "presentation": {
      "echo": true,
      "reveal": "always",
      "focus": false,
      "panel": "shared"
    }
  }]
}

Update VS Code build task to use yarn
Update VS Code build task to use yarn