Passing sourceLatitude/sourceLongitude as undefined breaks the path

[vvscode]

At the https://github.com/flexible-agency/react-native-map-link/blob/master/src/index.js#L42

we verify if params are in the options, but do not check the value, so for undefined we have

parseFloat(undefined); // NaN

for sure it can be fixed in the client code, but seems like nice to handle it inside the lib

[theneekz]

If this is so that you can open a single place in google maps, rather than directions to that place, see my patch

[vvscode]

@theneekz PR is welcome

[theneekz]

pr submitted