fix: update to android gradle v8

packages/flutter_mimir/android/build.gradle

@@ -1,5 +1,5 @@
-group 'com.gsconrad.flutter_mimir'
-version '0.0.1'
+group = "com.gsconrad.flutter_mimir"
+version = "0.0.1"
 
 buildscript {
     repositories {
@@ -9,7 +9,7 @@ buildscript {
 
     dependencies {
         // The Android Gradle Plugin knows how to build native code with the NDK.
-        classpath 'com.android.tools.build:gradle:7.1.2'
+        classpath("com.android.tools.build:gradle:8.1.0")
     }
 }
 
@@ -20,19 +20,34 @@ rootProject.allprojects {
     }
 }
 
-apply plugin: 'com.android.library'
+apply plugin: "com.android.library"
 
 android {
-    compileSdkVersion 31
+    namespace = "com.gsconrad.flutter_mimir"
 
-    defaultConfig {
-        minSdkVersion 16
-    }
+    // Bumping the plugin compileSdk version requires all clients of this plugin
+    // to bump the version in their app.
+    compileSdk = 35
+
+    // Use the NDK version
+    // declared in /android/app/build.gradle file of the Flutter project.
+    // Replace it with a version number if this plugin requires a specific NDK version.
+    // (e.g. ndkVersion "23.1.7779620")
+    ndkVersion = android.ndkVersion
 
     // Trigger the binary download/update over in CMakeLists.txt
     externalNativeBuild {
         cmake {
-            path "CMakeLists.txt"
+            path = "CMakeLists.txt"
         }
     }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+
+    defaultConfig {
+        minSdk = 21
+    }
 }