set license metadata and fix dependencies

[joergen7]

License Metadata

Observation

The Racket package manager flags this repository as having missing license metadata.

https://pkgs.racket-lang.org/package/quickcheck

Execution

Add license information to info.rkt

Fix Dependencies

Observation

Running a dependency check on the quickcheck package yields the following:

raco setup --no-docs --check-pkg-deps --unused-pkg-deps quickcheck

raco setup: unused dependencies detected
  for package: "quickcheck"
  on packages:
   "rackunit-gui"
   "rackunit-plugin-lib"
   "rackunit"
   "rackunit-doc"

Execution

Replace the run-time dependency on rackunit with rackunit-lib.