Update to PureScript 0.13 about purescript-flare

[sharkdp]

I probably won't have time to work on it myself, but in principle: yes.

[KovaxG]

Updated a dependency so the project will compile at least.

#32

[sharkdp]

Thank you. The tests look fine after building (see README). I pushed a new v6.0.0 tag. Unfortunately, pulp publish fails:

* Uploading documentation to Pursuit...
* Failed reading: not a valid json value
* ERROR: Expected an HTTP 201 response from Pursuit, got: 400

[FranklinChen]

I put flare into purescript/package-sets#473

[sharkdp]

Thank you