Added changelog for version 1.13.0. [skip ci]

Author: jlesage

appdefs.xml

@@ -109,6 +109,13 @@ Where:
     </documentation>
     <!-- Changelog of the application. -->
     <history>
+      <release>
+        <version>1.13.0</version>
+        <date>2021-02-09</date>
+        <change>Updated Nginx Proxy Manager to version 2.8.0.</change>
+        <change>Updated OpenResty to version 1.19.3.1.</change>
+        <change>Replaced the depricated GeoIP module by GeoIP2.</change>
+      </release>
       <release>
         <version>1.12.0</version>
         <date>2021-01-06</date>