add namespace for build.gradle

thermion_flutter/thermion_flutter/android/build.gradle

@@ -1,4 +1,4 @@
-group 'app.polyvox.filament'
+group 'dev.thermion.android'
 version '1.0-SNAPSHOT'
 
 buildscript {
@@ -25,6 +25,7 @@ apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 
 android {
+    namespace 'dev.thermion.android'
     compileSdkVersion 33
     ndkVersion '25.2.9519653'
     compileOptions {