Update dependencies and compile SDK version

* Using SDK version 30
* Bump Android Gradle Plugin to 4.2.1
* No need to specify build tools version, use defaults from Android Gradle Plugin
* Bump appcompat to 1.3.0
* Bump material to 1.3.0
* Bump recyclerview to 1.2.0
* Bump flexbox to 3.0.0 and get rid of jcenter repo
* Bump junit to 4.13.2

build.gradle

@@ -2,11 +2,11 @@
 
 buildscript {
     repositories {
-        jcenter()
         google()
+        mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.2'
+        classpath 'com.android.tools.build:gradle:4.2.1'
     }
 }
 
@@ -16,8 +16,8 @@ plugins {
 
 allprojects {
     repositories {
-        jcenter()
         google()
+        mavenCentral()
         maven { url "https://jitpack.io" }
     }
 }

chatkit/build.gradle

@@ -2,8 +2,7 @@ apply plugin: 'com.android.library'
 apply plugin: 'maven-publish'
 
 android {
-    compileSdkVersion 29
-    buildToolsVersion '29.0.2'
+    compileSdkVersion 30
 
     defaultConfig {
         minSdkVersion 14
@@ -41,10 +40,8 @@ android {
 }
 
 dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
-
-    implementation 'androidx.appcompat:appcompat:1.2.0'
-    implementation 'com.google.android.material:material:1.2.1'
-    implementation "com.google.android:flexbox:1.0.0"
-    implementation 'androidx.recyclerview:recyclerview:1.1.0'
+    implementation 'androidx.appcompat:appcompat:1.3.0'
+    implementation 'com.google.android.material:material:1.3.0'
+    implementation "com.google.android.flexbox:flexbox:3.0.0"
+    implementation 'androidx.recyclerview:recyclerview:1.2.0'
 }

sample/build.gradle

@@ -1,8 +1,7 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 29
-    buildToolsVersion '29.0.2'
+    compileSdkVersion 30
     defaultConfig {
         applicationId "com.stfalcon.chatkit.sample"
         minSdkVersion 14
@@ -31,15 +30,14 @@ android {
 dependencies {
     implementation project(':chatkit')
 
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
     androidTestImplementation('androidx.test.espresso:espresso-core:3.1.0', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    testImplementation 'junit:junit:4.13'
+    testImplementation 'junit:junit:4.13.2'
 
-    implementation 'androidx.appcompat:appcompat:1.2.0'
+    implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'androidx.cardview:cardview:1.0.0'
-    implementation 'com.google.android.material:material:1.2.1'
+    implementation 'com.google.android.material:material:1.3.0'
 
     //Picasso
     implementation "com.squareup.picasso:picasso:2.71828"