Change the "firebase.json" file's "predeploy" section from this: 

 "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run lint",
      "npm --prefix \"$RESOURCE_DIR\" run build"
    ]
  },
  
To this:

 "functions": {
    "predeploy": [
      "npm --prefix \"%RESOURCE_DIR%\" run lint",
      "npm --prefix \"%RESOURCE_DIR%\" run build"
    ]
  }