Moving @types dependencies to devDependencies

[barakshechter]

Moving the type dependencies to devDependencies since the compiled index.js has no direct need for them. The only hard dependency this library needs is cls-hooked.

[coveralls]

Coverage remained the same at 100.0% when pulling 74da837 on barakshechter:move-type-deps-to-dev-only into f6b63dc on skonves:master.

[barakshechter]

Hi @skonves ,

I was depending on your library when I noticed it had a hard dependency on express types, which theoretically only apply when developing in typescript.