Rename LICENSE.md and fix license in pom.xml

Author: joshuasing

LICENSE.md renamed to LICENSE

@@ -31,8 +31,8 @@
 
     <licenses>
         <license>
-            <name>GNU General Public License</name>
-            <url>https://www.gnu.org/licenses/gpl-3.0.html</url>
+            <name>ISC License</name>
+            <url>https://cvsweb.openbsd.org/src/share/misc/license.template?rev=HEAD</url>
         </license>
     </licenses>