[#270] Add compatibility with tasty-hedgehog 1.2.0.0

[dcastro]

Description

Problem: In order to be compliant with the stackage nightly, the test suite needs to buildable with tasty-hedgehog 1.2.0.0. At the moment, we have a constraint on tasty-hedgehog < 1.2.0.0 because that version deprecates the testProperty function (and encourages using testPropertyNamed instead), which we're still using.

Solution: we don't actually need to use either testProperty or testPropertyNamed, we can just use tasty-discover to collect all tests.

Related issues(s)

Fixed #270

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[gromakovsky]

Let's also bump the version before merging to make a new release?

[dcastro]

Let's also bump the version before merging to make a new release?

Done. Also added @since haddock metadata, which I think we should start using going forward, what do you think?

[gromakovsky]

Done. Also added @since haddock metadata, which I think we should start using going forward, what do you think?

Yes, sounds good, just a bit hard to keep in mind when you don't develop libraries on a regular basis :slightly_smiling_face: