ci: Update release workflow to include impure flag in Nix command

The Nix command now uses the `--impure` flag and `just` to run the release. This ensures compatibility with the development environment and improves command execution reliability.

Author: flemzord

.github/workflows/releases.yml

@@ -19,7 +19,7 @@ jobs:
           token: ${{ secrets.NUMARY_GITHUB_TOKEN }}
       - run: >
           /nix/var/nix/profiles/default/bin/nix --extra-experimental-features "nix-command" --extra-experimental-features "flakes"
-          develop release
+          develop --impure --command just release
         env:
           GITHUB_TOKEN: ${{ secrets.NUMARY_GITHUB_TOKEN }}
           SPEAKEASY_API_KEY: ${{ secrets.SPEAKEASY_API_KEY }}