fix:Made it release apk

Author: angrezichatterbox

android/app/build.gradle

@@ -64,4 +64,7 @@ flutter {
     source '../..'
 }
 
-dependencies {}
+dependencies {
+    implementation 'com.google.errorprone:error_prone_annotations:2.23.0'
+    implementation 'com.google.code.findbugs:jsr305:3.0.2'
+}

android/app/proguard-rules.pro

@@ -0,0 +1,10 @@
+# Keep Google Error Prone annotations
+-keep class com.google.errorprone.annotations.CanIgnoreReturnValue { *; }
+-keep class com.google.errorprone.annotations.CheckReturnValue { *; }
+-keep class com.google.errorprone.annotations.Immutable { *; }
+-keep class com.google.errorprone.annotations.RestrictedApi { *; }
+
+# Keep javax annotations
+-keep class javax.annotation.Nullable { *; }
+-keep class javax.annotation.concurrent.GuardedBy { *; }
+