revert change to use lts-19.32

revert change to use lts-19.32

This reverts commit 15dd7fe84b2aa13531c80adb00efa82469724845.

aws 0.23 is not used any longer, so read-only S3 import won't be
supported yet when building with stack.

That commit broke the build on windows, because the new version of Win32 that
was included (because the old one does not work with this lts version)
needs a version of filepath that is newer than the one bundled with the
ghc in that lts version. It is not possible to override that to a newer
filepath.

Seems that the only solution to get aws 0.23 will be to wait for a ghc that
contains filepath 1.4.100.0. No ghc yet contains it. (Backporting the Win32
fix to a point release version that does not include this bleeding edge
filepath would also resolve it, but seems unlikely to happen.)

Sponsored-by: Jarkko Kniivilä on Patreon