Remove jcenter, use minSdk from root

Author: pnthach95

android/build.gradle

@@ -4,7 +4,7 @@ buildscript {
 
   repositories {
     google()
-    jcenter()
+    mavenCentral()
   }
 
   dependencies {
@@ -29,7 +29,7 @@ android {
   compileSdkVersion getExtOrIntegerDefault('compileSdkVersion')
   buildToolsVersion getExtOrDefault('buildToolsVersion')
   defaultConfig {
-    minSdkVersion 21
+    minSdkVersion getExtOrIntegerDefault('minSdkVersion')
     targetSdkVersion getExtOrIntegerDefault('targetSdkVersion')
     versionCode 1
     versionName "1.0"
@@ -52,7 +52,6 @@ android {
 
 repositories {
   mavenCentral()
-  jcenter()
   google()
 
   def found = false

android/gradle.properties

@@ -2,3 +2,4 @@ MultipleImagePicker_kotlinVersion=1.3.50
 MultipleImagePicker_compileSdkVersion=29
 MultipleImagePicker_buildToolsVersion=29.0.2
 MultipleImagePicker_targetSdkVersion=29
+MultipleImagePicker_minSdkVersion=21