Added -dontwarn proguard rule for java sdk notnull (#1237)

Author: Langston Smith

MapboxAndroidDemo/proguard-rules.pro

@@ -80,7 +80,7 @@
 -dontwarn java.awt.Color
 -dontwarn com.mapbox.api.staticmap.v1.models.StaticMarkerAnnotation
 -dontwarn com.mapbox.api.staticmap.v1.models.StaticPolylineAnnotation
-
+-dontwarn com.sun.istack.internal.NotNull
 
 ## Android architecture components: Lifecycle
 # LifecycleObserver's empty constructor is considered to be unused by proguard

MapboxAndroidWearDemo/proguard-rules.pro

@@ -91,6 +91,7 @@
 -dontwarn java.awt.Color
 -dontwarn com.mapbox.api.staticmap.v1.models.StaticMarkerAnnotation
 -dontwarn com.mapbox.api.staticmap.v1.models.StaticPolylineAnnotation
+-dontwarn com.sun.istack.internal.NotNull
 
 # Mapbox
 -keep class com.mapbox.android.telemetry.**