Update choldgraf metadata

Co-authored-by: Chris Holdgraf <choldgraf@gmail.com>

Author: jasongrout

about.html

@@ -365,6 +365,8 @@
   - name: Chris Holdgraf
     photo: Chris_Holdgraf.png
     gh_handle: choldgraf
+    linkedin: https://www.linkedin.com/in/chrisholdgraf/
+    bluesky_handle: choldgraf.com
     twitter_handle: choldgraf
     personal: http://chrisholdgraf.com
   - name: Ana Ruvalcaba