Fix Proguard issues

[Guardiola31337]

Warning: com.mapbox.mapboxsdk.plugins.locationlayer.LocationLayerOptions$Builder: can't find referenced class com.google.auto.value.AutoValue$Builder
Warning: com.mapbox.mapboxsdk.plugins.locationlayer.LocationLayerOptions$Builder: can't find referenced class com.google.auto.value.AutoValue$Builder

• Fixes AutoValue Proguard rules in geojson, locationlayer, offline and places plugins so that builds with Proguard enabled don't fail.

The CI Proguard check (Build release to test ProGuard rules step) was ✅ because of

mapbox-plugins-android/app/proguard-rules.pro

Lines 3 to 4 in 7a676e4

	-keep class com.google.**
	-dontwarn com.google.**

which include AutoValue classes (note that com.google.auto.value is included in com.google.**).

We were only taking into account AutoValue classes and not AutoValue$Builder ones 👇

mapbox-plugins-android/plugin-locationlayer/proguard-consumer.pro

Line 5 in 7a676e4

-dontwarn com.google.auto.value.AutoValue

We should remove Mapbox Plugin testapp ProGuard rules after mapbox/mapbox-events-android#109 lands because Proguard rules will be properly managed upstream.

cc @cammace @LukasPaczos @tobrun

[Guardiola31337]

cc'ing @danesfeder for visibility