add proguard rules to android builds

android/build.gradle

@@ -30,6 +30,7 @@ android {
         targetSdkVersion 31
         versionCode 1
         versionName '3.12.4'
+        consumerProguardFiles 'proguard-rules.pro'
     }
     lintOptions {
         disable 'InvalidPackage'

android/proguard-rules.pro

@@ -0,0 +1,4 @@
+--dontwarn com.huawei.**
+
+-dontwarn com.google.android.play.integrity.**
+-dontwarn com.google.android.play.core.integrity.**

example/android/app/build.gradle

@@ -42,6 +42,8 @@ android {
             // TODO: Add your own signing config for the release build.
             // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig signingConfigs.debug
+            minifyEnabled true
+            shrinkResources true
         }
     }