Upgrade to latest Flutter version (fix Gradle and other errors)

android/app/build.gradle

@@ -1,6 +1,7 @@
 plugins {
     id "com.android.application"
     id "kotlin-android"
+    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
     id "dev.flutter.flutter-gradle-plugin"
 }
 
@@ -29,33 +30,30 @@ if (keystorePropertiesFile.exists()) {
 }
 
 android {
-    namespace "dev.imranr.obtainium"
-    compileSdk flutter.compileSdkVersion
-    ndkVersion flutter.ndkVersion
+    namespace = "dev.imranr.obtainium"
+    compileSdk = flutter.compileSdkVersion
+    ndkVersion = flutter.ndkVersion
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
-        targetCompatibility JavaVersion.VERSION_1_8
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
     }
 
     kotlinOptions {
-        jvmTarget = '1.8'
-    }
-
-    sourceSets {
-        main.java.srcDirs += 'src/main/kotlin'
+        jvmTarget = JavaVersion.VERSION_1_8
     }
 
     defaultConfig {
-        applicationId "dev.imranr.obtainium"
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId = "dev.imranr.obtainium"
         // You can update the following values to match your application needs.
-        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
-        minSdkVersion 24
-        targetSdkVersion flutter.targetSdkVersion
-        versionCode flutterVersionCode.toInteger()
-        versionName flutterVersionName
+        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        minSdk = 24
+        targetSdk = flutter.targetSdkVersion
+        versionCode = flutter.versionCode
+        versionName = flutter.versionName
     }
-    
+
     flavorDimensions "flavor"
 
     productFlavors {
@@ -77,6 +75,7 @@ android {
             storePassword keystoreProperties['storePassword']
         }
     }
+
     buildTypes {
         release {
             signingConfig signingConfigs.release
@@ -89,11 +88,7 @@ android {
 }
 
 flutter {
-    source '../..'
-}
-
-repositories {
-    maven { url 'https://jitpack.io' }
+    source = "../.."
 }
 
 ext.abiCodes = ["x86_64": 1, "armeabi-v7a": 2, "arm64-v8a": 3]