Update package maintainers

This commit updates the package maintainers as the project's governance has changed a bit.

Author: urfeex

package.xml

@@ -9,7 +9,11 @@
   <author>Felix Exner</author>
   <author>Lea Steffen</author>
   <author>Tristan Schnell</author>
-  <maintainer email="[email protected]">Felix Exner</maintainer>
+
+  <maintainer email="[email protected]">Felix Exner</maintainer>
+  <maintainer email="[email protected]">Rune Søe-Knudsen</maintainer>
+  <maintainer email="[email protected]">Universal Robots A/S</maintainer>
+  
   <license file="LICENSE_apache_2_0">Apache-2.0</license>
   <license file="include/ur_client_library/queue/LICENSE.md">BSD-2-Clause</license>
   <license file="include/ur_client_library/queue/atomicops.h">Zlib</license>