Goal: Build a static PostgREST 7.0.0 executable

• Build dynamic executable from Hackage based on static-haskell-nix nixpkgs (run nix-build -A dynamic)
• Build static executable based on static-haskell-nix defaults (recommended: cachix use static-haskell-nix; run nix-build -A static)
• Use integer-simple

Continued here: PostgREST/postgrest#1494

• Switch to a newer pinned nixpkgs version
• Use a newer compiler, ghc883
• Replace the Hackage version with using callCabal2nix in the PostgREST respository