Update Nix team (#1911)

I'm just a contributor for now, having left for organizational reasons.
Glad that I could. Didn't feel that way until last year.

Being part of the Nix team was fun and challenging. Great energy from
new members Sergei and Taeer.
Love Mic92's hands-on mode of existence.
John's been doing amazing work to make Nix solve more problems with
dyndrvs and cross cutting concerns like settings system and JSON
Schemas. And Eelco's been doing great work to move fetching forward (for
flakes etc). And of course lots of respect for the whole team for their
efforts over the years.

Author: roberth

core/src/content/teams/110_nix.mdx

@@ -8,9 +8,6 @@ members:
   - name: Thomas Bereknyei
     discourse: tomberek
     title:
-  - name: Robert Hensing
-    discourse: roberth
-    title:
   - name: John Ericson
     discourse: Ericson2314
     title: