Force bash usage in dev-shell. Should fix #236

Dependencies

• [2] DWQCLOPQ Tweaks for nix-shell

Change contents

• replacement in dev-shell at line 1
  [2.1]→[2.2:13](∅→∅)
  − #! /bin/sh
  [2.1]

  [2.13]
  + #! /usr/bin/env bash