[app] Fix android codename (#213)

R8 bug

app/src/main/java/io/github/lsposed/manager/ui/fragment/StatusDialogBuilder.java

@@ -130,7 +130,6 @@ public class StatusDialogBuilder extends AlertDialog.Builder {
 
     private String getAndroidVersion() {
         switch (Build.VERSION.SDK_INT) {
-            case 26:
             case 27:
                 return "Oreo";
             case 28:

build.gradle

@@ -5,8 +5,12 @@ buildscript {
     repositories {
         google()
         jcenter()
+        maven {
+            url 'https://storage.googleapis.com/r8-releases/raw'
+        }
     }
     dependencies {
+        classpath 'com.android.tools:r8:3.0.25-dev'
         classpath 'com.android.tools.build:gradle:4.1.2'
         classpath 'org.eclipse.jgit:org.eclipse.jgit:5.10.0.202012080955-r'
     }