Prepare minimal release 1.3.1

Author: purejava

README.md

@@ -102,7 +102,7 @@ As the according jar has a size of ~9,6M, I decided to provide a **reduced varia
 <dependency>
     <groupId>org.purejava</groupId>
     <artifactId>libappindicator-gtk3-java-minimal</artifactId>
-    <version>1.3.0</version>
+    <version>1.3.1</version>
 </dependency>
 ```
 ### libappindicator-gtk3-java-minimal 1.1.0 - minimal is compatible to both libraries

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>org.purejava</groupId>
     <artifactId>libappindicator-gtk3-java-minimal</artifactId>
-    <version>1.3.1-SNAPSHOT</version>
+    <version>1.3.1</version>
 
     <name>libappindicator-gtk3-java-minimal</name>
     <description>Java bindings for libayatana-appindicator and libappindicator-gtk3 in 100% pure Java</description>