Upgrade react-native-github Android to support API level 19+

Summary:
This diff upgrades react-native-github Android to support API level 19+

changelog: [Android][Deprecated] Deprecate support of Android API levels 16 to 18. The new minSDK version will be 19+ moving forward

Reviewed By: JoshuaGross

Differential Revision: D22734208

fbshipit-source-id: b052721c8cfb44f8d74cf4bbb5b7a769e544d1d9

RNTester/android/app/build.gradle

@@ -121,7 +121,7 @@ android {
 
     defaultConfig {
         applicationId "com.facebook.react.uiapp"
-        minSdkVersion 18
+        minSdkVersion 19
         targetSdkVersion 29
         versionCode 1
         versionName "1.0"

ReactAndroid/build.gradle

@@ -166,7 +166,7 @@ task prepareJSC {
         def jscPackagePath = findNodeModulePath(projectDir, "jsc-android")
         if (!jscPackagePath) {
             throw new GradleScriptException("Could not find the jsc-android npm package", null)
-        } 
+        }
 
         def jscDist = file("$jscPackagePath/dist")
         if (!jscDist.exists()) {
@@ -223,7 +223,7 @@ task downloadNdkBuildDependencies {
 def findNodeModulePath(baseDir, packageName) {
     def basePath = baseDir.toPath().normalize()
     // Node's module resolution algorithm searches up to the root directory,
-    // after which the base path will be null 
+    // after which the base path will be null
     while (basePath) {
         def candidatePath = Paths.get(basePath.toString(), "node_modules", packageName)
         if (candidatePath.toFile().exists()) {
@@ -382,7 +382,7 @@ android {
     }
 
     defaultConfig {
-        minSdkVersion(16)
+        minSdkVersion(19)
         targetSdkVersion(28)
         versionCode(1)
         versionName("1.0")