🐛 Remove jcenter / use modern versions (#30)

* fix(android, build): remove jcenter / use modern versions

* fix(android): use default versions with wider compatibility

Android gradle plugin of 7.0.3 requires a minimum gradle of 7 which it turns out many don't have
If you do have gradle 7 though, you may have a compatibility issue with Java 8
Sticking to gradle plugin 4 for a bit, and compile version 30 (rapidly becoming most common) should
yield maximum compatibility

Author: mikehardy

android/build.gradle

@@ -1,11 +1,17 @@
-
 buildscript {
-    repositories {
-        jcenter()
-    }
-
-    dependencies {
-        classpath 'com.android.tools.build:gradle:1.3.1'
+    // The Android Gradle plugin is only required when opening the android folder stand-alone.
+    // This avoids unnecessary downloads and potential conflicts when the library is included as a
+    // module dependency in an application project.
+    if (project == rootProject) {
+        repositories {
+            mavenCentral()
+            google()
+        }
+        def buildGradleVersion = ext.has('buildGradlePluginVersion') ? ext.get('buildGradlePluginVersion') : '4.2.2'
+
+        dependencies {
+            classpath "com.android.tools.build:gradle:$buildGradleVersion"
+        }
     }
 }
 
@@ -16,12 +22,12 @@ def safeExtGet(prop, fallback) {
 }
 
 android {
-    compileSdkVersion safeExtGet('compileSdkVersion', 26)
-    buildToolsVersion safeExtGet('buildToolsVersion', '26.0.3')
+    compileSdkVersion safeExtGet('compileSdkVersion', 30)
+    buildToolsVersion safeExtGet('buildToolsVersion', '30.0.3')
 
     defaultConfig {
         minSdkVersion safeExtGet('minSdkVersion', 16)
-        targetSdkVersion safeExtGet('targetSdkVersion', 26)
+        targetSdkVersion safeExtGet('targetSdkVersion', 30)
         versionCode 1
         versionName "1.0"
     }
@@ -32,6 +38,11 @@ android {
 
 repositories {
     mavenCentral()
+    google()
+    maven {
+        // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
+        url "$rootDir/../node_modules/react-native/android"
+    }
 }
 
 dependencies {