doc(readme):修改文档

Author: JunhuaLin

README.md

@@ -15,10 +15,14 @@ MultiTypeAdapter的优点如下：
 在build.gradle中添加如下代码：
 ```groovy
 dependencies {
-    compile 'cn.junhua.android.adapter:multitypeadapter:3.0.0-beta'
+    implementation 'cn.junhua.android.adapter:multitypeadapter:3.0.0-beta'
 }
 ```
 
+注：3.x版本较2.x版本改动非常大，不兼容之前版本。2.x最后一版``2.3.3``
+
+
+
 关系图：
 
 ![关系图](https://github.com/JunhuaLin/MultiTypeAdapter/blob/master/photo/关系图3.png)

app/build.gradle

@@ -25,7 +25,7 @@ android {
 }
 
 dependencies {
-    compile fileTree(include: ['*.jar'], dir: 'libs')
+    implementation fileTree(include: ['*.jar'], dir: 'libs')
     androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })