ci: Reduce reviewers scope (#200)

From a discussion in the product<>engineering retro today. The
tech-devs team is quite broad, and ends up with people receiving a lot
of emails.

The same as climatepolicyradar/navigator-admin-frontend#84.

.github/CODEOWNERS

@@ -12,4 +12,4 @@
 # review when someone opens a pull request. Teams should
 # be identified in the format @org/team-name. Teams must have
 # explicit write access to the repository.
-* @climatepolicyradar/tech-devs
+* @climatepolicyradar/software