Bump for GHC 8.6.1

[lambdageek]

I actually have a branch ghc-861-travis that bumps our upper bounds.

But I can't test it because I run into build issues on travis.

At the moment, I'm building with --allow-newer=base,containers,binary and it gets as far as rebuilding Cabal-2.2.0.1 (b/c reasons...) and then breaks because that version of Cabal uses a deprecated function from containers and containers-0.6 removed it:

Distribution/PackageDescription/Configuration.hs:222:39: error:
    • Data.Map.insertWith' is gone. Use Data.Map.Strict.insertWith.
    • In the first argument of ‘Map.foldrWithKey’, namely
        ‘(Map.insertWith' combine)’
      In the expression:
        Map.foldrWithKey
          (Map.insertWith' combine) (unDepMapUnion xs) (unDepMapUnion ys)
      In an equation for ‘union’:
          union
            = Map.foldrWithKey
                (Map.insertWith' combine) (unDepMapUnion xs) (unDepMapUnion ys)
    |
222 |         let union = Map.foldrWithKey (Map.insertWith' combine)
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^
Failed to install Cabal-2.2.0.1
cabal: Error: some packages failed to install:
Cabal-2.2.0.1-FcabUjH9MHb6X9mJWWeEmL failed during the building phase. The
exception was:
ExitFailure 1
bifunctors-5.5.3-DKOZCSeXJl2DeGxgt9KwMz depends on bifunctors-5.5.3 which
failed to install.
cabal-doctest-1.0.6-4W568SY7EO64yyE1vbTC6r depends on cabal-doctest-1.0.6
which failed to install.
comonad-5.0.4-E8iDC86E3q2Bfy0bXvSixA depends on comonad-5.0.4 which failed to
install.
distributive-0.6-KKdNmBTJnxYKhiwNjoFylh depends on distributive-0.6 which
failed to install.
profunctors-5.3-3nl0iE8l74LLcBGaPKnj2w depends on profunctors-5.3 which failed
to install.

So... we wait.

[lambdageek]

Waiting helped. #32 and #33 should be ready to go soon.

After #32, I'm going to release unbound-generics-0.3.4 from the maint-0.3 branch.

[lambdageek]

GHC-8.6.1 is supported on the maint-0.3 branch (unbound-generics-0.3.4 on Hackage) and on master.