ghc-invariant-0.5.3-bp153.1.20

- Drop obsolete group attributes.

- Update invariant to version 0.5.3.
  [#] 0.5.3 [2019.05.02]
  * Implement `foldMap'` in the `Foldable` instance for `WrappedFunctor` when
    building with `base-4.13` or later.

- Update invariant to version 0.5.2.
  [#] 0.5.2 [2019.04.26]
  * Support `th-abstraction-0.3.0.0` or later.
  * Only incur a `semigroups` dependency on old GHCs.

- Update Cabal build instructions for more accurate dependencies on
  th-abstraction.

- Add invariant at version 0.5.1.

- Update to version 0.4.2 with cabal2obs.

- Update to version 0.4.1 with cabal2obs.

- Update to version 0.4 revision 0 with cabal2obs.

- Update to version 0.3.1 revision 0 with cabal2obs.