Add Mock Provider boolean on each location update

[chaitanyadeorukhkar]

Does any other open PR do the same thing?

No

What issue is this PR fixing?

This adds a check to whether the returned location is authentic or mocked

How did you test this PR?

Tested it on my application where I am checking for mock providers

1. Set showsUserLocation={true} in MapView component
2. Set 'google' as your map provider
3. Listen for onUserLocationChange which will return a callback with lat,long,speed,accuracy & boolean for isFromMockProvider

(Works only for Android)
I have tested this on Android (real device)

[rborn]

@deorukhkarchaitanya thanks for the PR 🤗
If I understand this right isFromMockProvider is available only on android.

So please update the docs as well, specifying also the above (if correct of course)

[chaitanyadeorukhkar]

@rborn Sorry for that. Let me just run a check and update it.

Update:
@rborn You are right. I'll be more careful next time. Thanks. :)

[rborn]

@deorukhkarchaitanya I mean the real docs page, not only the PR text https://github.com/react-community/react-native-maps/blob/master/docs/mapview.md 😄

[chaitanyadeorukhkar]

Updated the docs. Thanks again for the guidance :)