Update Try PureScript for 0.14

[thomashoneyman]

Once the 0.14 package set has been released, we'll need to:

• Update the package sets in use in this repository
• Verify that the package set behaves properly in Try PureScript
• Perform any other last-minute checks

Three checks we should definitely complete before deploying a new version on the new package set:

• Verify that newtypes with their constructors in scope only for a coercion do not produce warnings
• Verify pattern guards are handled correctly (see purescript/purescript#2801)
• Verify all of the Try PureScript examples continue to behave correctly with the new package set.
• Verify that the new package set won't overwhelm the memory in the server, and add the steps to check this to the maintainers' documentation.

[JordanMartinez]

Can this issue be closed now?