bump foxy to 3.1.2 for release

Author: SteveMacenski

package.xml

@@ -2,7 +2,7 @@
 <?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
 <package format="3">
   <name>robot_localization</name>
-  <version>3.1.1</version>
+  <version>3.1.2</version>
   <description>Provides nonlinear state estimation through sensor fusion of an abritrary number of sensors.</description>
 
   <author email="[email protected]">Tom Moore</author>