Invalid request(Android) about flutter_google_places_sdk

[maxbritto]

@matanshukry : you can now close this one after 0.3.7

[maxbritto]

I've investigated this and the problem is that some filters are more complicated than just lowercasing it.
For example : CITIES should be converted to either (cities) , locality or administrative_area_level_3

Prior to the latest update the google sdks were expecting an enum value for the PlaceTypeFilter but now it requires a list of strings.

Current version of this SDK sends the enum values from the dart code to each platform and each platform has the responsibility to convert it to a String.

Some platform codes was doing things right (for example the web platform was converting the filters to their correct values), but other platforms were not (android is just lowercasing it).

I think we should convert it to a list of string on the Dart side, and then send the list to each platform.
each platform will only have to forward this list to its own SDK.

I've written the code, but I cannot figure out how to test it locally because each package depends on published versions and my fix changes many packages.

My patch should fix this bug, but also #48 and #57
I just need to test it before I can submit the PR

@matanshukry : is there a way to test changes locally, without publishing the packages or changing all the pubspecs of each platform ?