Update build.gradle

Author: matthewtsmith

flutter_appauth/android/build.gradle

@@ -24,6 +24,10 @@ apply plugin: 'com.android.library'
 android {
     compileSdkVersion 30
 
+    if (project.android.hasProperty("namespace")) {
+        namespace 'io.crossingthestreams.flutterappauth'
+    }
+
     defaultConfig {
         minSdkVersion 16
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -35,4 +39,4 @@ android {
 
 dependencies {
     implementation 'net.openid:appauth:0.10.0'
-}
+}