Bump version from v1.2.0 to v1.3.0-SNAPSHOT because of upcoming API incompatible change

Author: vorburger

pom.xml

@@ -5,7 +5,7 @@
 
   <groupId>com.github.multiformats</groupId>
   <artifactId>java-multibase</artifactId>
-  <version>v1.2.0</version>
+  <version>v1.3.0-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <name>multibase</name>