Changelog of @hackage/lca 0.4

0.4 [2021.02.17]

lca now always exports null and length functions that are always specialized to Path, i.e.,
```
length :: Path a -> Int
null :: Path a -> Bool
```
Previously, these specialized versions of null and length were only exported with GHC 7.8 or older, and for more recent GHCs, the Data.Foldable versions were exported instead. The exported API is now uniform across all supported versions of GHC.
The build-type has been changed from Custom to Simple. To achieve this, the doctests test suite has been removed in favor of using cabal-docspec to run the doctests.

Updated to build without warnings in the wake of GHC 7.10.
Use (and re-export) the new overloaded null and length from Prelude on GHC 7.10+
Modified mkeep, mdrop and mlca to parameterize them by monoid homomorphisms. This permits cheaper summaries to be calculated over the dropped path, when only a portion of the information in the path is required.

Improved documentation to also note that this package also provides an improvement in the online version of the level ancestor problem.