update version to 1.2

Author: celeduc

README.md

@@ -34,7 +34,7 @@ for Maven, you can add the follwing sections to your POM.XML:
     <dependency>
       <groupId>com.github.multiformats</groupId>
       <artifactId>java-multihash</artifactId>
-      <version>v1.1.0</version>
+      <version>v1.2.0</version>
     </dependency>
   </dependencies>
 ```

build.xml

@@ -40,7 +40,7 @@
         <attribute name="Class-Path" value="${manifest_cp}"/>
         <attribute name="Implementation-Vendor" value="io.ipfs"/>
         <attribute name="Implementation-Title" value="multihash"/>
-        <attribute name="Implementation-Version" value="1.1.0"/>
+        <attribute name="Implementation-Version" value="1.2.0"/>
       </manifest>
     </jar>
   </target>

pom.xml

@@ -4,7 +4,7 @@
 
 	<groupId>io.ipfs</groupId>
 	<artifactId>multihash</artifactId>
-	<version>1.1.0</version>
+	<version>1.2.0</version>
 	<packaging>jar</packaging>
 
 	<name>multihash</name>