vue/no-mutating-props should allow for mutating properties of a prop

[pimlie]

What rule do you want to change?
vue/no-mutating-props

Does this change cause the rule to produce more or fewer warnings?
Fewer warnings

How will the change be implemented? (New option, new default behavior, etc.)?
New default behaviour should be fine I suppose

Please provide some example code that this change will affect:

props: {
  myObjectProp: {
    type: Object,
    required: true,
  }
},
methods: {
  doSomething() {
    this.myObjectProp.someKey = 'change' // <- should not trigger an error

    this.myObjectProp = { // <- should trigger an error
       someKey: 'new' 
    }
  }
}

What does the rule currently do for this code?
Trigger an error

What will the rule do after it's changed?
Nothing

Additional context

See the example, if you pass an object as property it should be fine to mutate its properties.

[ota-meshi]

Thank you for posting this issue.

However, it's duplicate of #1314.