Add A. Rosien to contributors.yml

DAFFODIL-2693
diff --git a/site/_data/contributors.yml b/site/_data/contributors.yml
index 57338b6..faedae4 100644
--- a/site/_data/contributors.yml
+++ b/site/_data/contributors.yml
@@ -96,3 +96,9 @@
   apacheId: shanedell
   githubId: shanedell
   role: PMC
+
+- first: Adam
+  last: Rosien
+  apacheId: arosien
+  githubId: arosien
+  role: PMC