fix(deploy-docs): remove unnecessary devshell prelude

- remove `nix-channel --update`

Signed-off-by: Cameron Smith <cameron.ray.smith@gmail.com>

Author: cameronraysmith

.github/workflows/deploy-docs.yaml

@@ -82,7 +82,6 @@ jobs:
           SOPS_AGE_KEY: ${{ secrets.CI_AGE_KEY }}
         run: |
           df -h
-          nix-channel --update
           nix develop --accept-flake-config -c just docs-build
           df -h