DEVELOPERS: add Roy Kollen Svendsen for a number of qt6 packages

Roy recently introduced a number of additional qt6 packages, let's
add him to the DEVELOPERS file for those packages.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -2798,6 +2798,16 @@ F:	support/testing/tests/package/test_openssh.py
 F:	support/testing/tests/package/test_python_mako.py
 F:	toolchain/
 
+N:	Roy Kollen Svendsen <roykollensvendsen@gmail.com>
+F:	package/qt6/qt6declarative/
+F:	package/qt6/qt6languageserver/
+F:	package/qt6/qt6mqtt/
+F:	package/qt6/qt6shadertools/
+F:	package/qt6/qt6tools/
+F:	package/qt6/qt6virtualkeyboard/
+F:	package/qt6/qt6wayland/
+F:	package/qt6/qt6websockets/
+
 N:	Rufus Segar <rhs@riseup.net>
 F:	package/agent-proxy/