Update version to 5.2.1.

Author: michael-rapp

README.md

@@ -35,7 +35,7 @@ Alternatively, the library can be added to your Android app as a Gradle dependen
 
 ```groovy
 dependencies {
- compile 'com.github.michael-rapp:android-material-dialog:5.2.0'
+ compile 'com.github.michael-rapp:android-material-dialog:5.2.1'
 }
 ```
 

gradle.properties

@@ -1,5 +1,5 @@
-VERSION_NAME=5.2.0
-VERSION_CODE=59
+VERSION_NAME=5.2.1
+VERSION_CODE=60
 BUILD_TOOLS_VERSION=28.0.3
 TARGET_SDK_VERSION=28
 MIN_SDK_VERSION=14