Update to purescript 0.12

[dawehner]

I'm by no means a purescript expect but it least the test didn't fail anymore with 0.12

$ yarn test
yarn run v1.12.3
$ pulp build -I test -- --censor-lib --strict --stash && pulp test
* Building project in /Users/dawehner/Projects/learn-purescript/bloom-filter/purescript-conditional
Compiling Test.Conditional
Compiling Test.Main
           Src   Lib   All
Warnings   0     0     0
Errors     0     0     0
* Build successful.
* Building project in /Users/dawehner/Projects/learn-purescript/bloom-filter/purescript-conditional
           Src   Lib   All
Warnings   0     0     0
Errors     0     0     0
* Build successful.
* Running tests...
→ Suite: ifelse
  ✓ Passed: should return the same value as the equivalent if else statement

All 1 tests passed! 🎉
* Tests OK.
✨  Done in 4.40s.