MAINTAINERS: Add myself to mcu manager as collaborator

Add myself to mcu manager as collaborator

Signed-off-by: Jamie McCrae <jamie.mccrae@lairdconnect.com>
diff --git a/MAINTAINERS.yml b/MAINTAINERS.yml
index c6fe5dd..1c670b2 100644
--- a/MAINTAINERS.yml
+++ b/MAINTAINERS.yml
@@ -1072,6 +1072,8 @@
     status: maintained
     maintainers:
         - de-nordic
+    collaborators:
+        - lairdjm
     files:
         - subsys/mgmt/mcumgr/
         - include/mgmt/mcumgr/