bug: 修复ripple在低版本不兼容的问题

imageeditlibrary/src/main/res/drawable-v21/image_edit_ripple.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ripple xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:color="#ffffff"
+    tools:ignore="NewApi">
+    <item android:drawable="@drawable/image_edit_click_ripple"/>
+</ripple>

imageeditlibrary/src/main/res/drawable/image_edit_click_ripple_normal.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/image_editor_main_backgroud" />
+    <corners android:radius="2dp" />
+</shape>

imageeditlibrary/src/main/res/drawable/image_edit_ripple.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
-<ripple xmlns:android="http://schemas.android.com/apk/res/android"
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
-    android:color="#ffffff"
-    tools:ignore="NewApi">
-    <item android:drawable="@drawable/image_edit_click_ripple"/>
-</ripple>
+    android:color="#ffffff">
+    <item android:drawable="@drawable/image_edit_click_ripple" android:state_pressed="true"/>
+    <item android:drawable="@drawable/image_edit_click_ripple_normal"/>
+</selector>

imageeditlibrary/src/main/res/values/colors.xml

@@ -1,6 +1,7 @@
 <resources>
     <color name="image_editor_white">#ffffff</color>
     <color name="image_editor_main_backgroud">#4f000000</color>
+    <color name="image_editor_main_backgroud_normal">#33000000</color>
     <color name="image_editor_materialcolorpicker__white">#ffffff</color>
     <color name="image_editor_materialcolorpicker__red">#f44336</color>
     <color name="image_editor_materialcolorpicker__green">#4caf50</color>