Abstract proguard rules at package level (#1247)

uni/android/app/proguard-rules.pro

@@ -20,10 +20,13 @@
 # hide the original source file name.
 #-renamesourcefileattribute SourceFile
 
-# The 6 lines below are added to fix #1243
--dontwarn com.google.errorprone.annotations.CanIgnoreReturnValue
--dontwarn com.google.errorprone.annotations.CheckReturnValue
--dontwarn com.google.errorprone.annotations.Immutable
--dontwarn com.google.errorprone.annotations.RestrictedApi
--dontwarn javax.annotation.Nullable
--dontwarn javax.annotation.concurrent.GuardedBy
+# These are annotations related to static analysis tools. Proguard 
+#  tries to optimize/obfuscate the bundle, it needs all
+#  packages to be present. Because these annotations do not exist
+#  at optimize time, it will warn us that it cannot find those packages.
+# Unfortunaly, AFAIK there's no real way to packages include their "own"
+#  proguard or some of them just do not do it, so we sometimes need to handle it
+#  when we add a new dependency. 
+
+-dontwarn com.google.errorprone.annotations.*
+-dontwarn javax.annotation.*