MAINTAINERS: Add collaborator for lora

Add Marcin as the collaborator for lora.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

MAINTAINERS.yml

diff --git a/MAINTAINERS.yml b/MAINTAINERS.yml
index 16ca0e2..ea79c20 100644
--- a/MAINTAINERS.yml
+++ b/MAINTAINERS.yml
@@ -645,6 +645,8 @@
     status: maintained
     maintainers:
         - Mani-Sadhasivam
+    collaborators:
+        - mniestroj
     files:
         - drivers/lora/
         - include/drivers/lora.h