codex.cabal: use local codex library, not already installed one
codex.cabal: use local codex library, not already installed one

I've noticed it when updated to codex-0.5.0.1 from hackage.
It's executable contained dependency on codex-0.5.0.0 library.

Use local just-built library.

Signed-off-by: Sergei Trofimovich <df7d2cee2e7ececeb2368216a0f9d0537fd32149@google.com>

aloiscochard/codex