Revert "stack.yaml: Updated to lts-19.16"

This reverts commit b5dc04099e.

Broke windows build, because the new lts updates Win32 to a version that
lacks a function that git-annex needs. git-annex.cabal depends on an
older Win32, and so stack build fails.

Will need to wait to update stack.yaml until this is fixed
https://github.com/haskell/win32/issues/208
and is in a new LTS release.

stack.yaml

@@ -12,13 +12,17 @@ flags:
     gitlfs: true
 packages:
 - '.'
-resolver: lts-19.16
+resolver: lts-18.13
 extra-deps:
 - IfElse-0.85
-- aws-0.22.1
+- aws-0.22
 - bloomfilter-2.0.1.0
 - git-lfs-1.2.0
-- http-client-restricted-0.0.5
+- http-client-restricted-0.0.4
 - network-multicast-0.3.2
 - sandi-0.5
 - torrent-10000.1.1
+- base16-bytestring-0.1.1.7
+- base64-bytestring-1.0.0.3
+- bencode-0.6.1.1
+- http-client-0.7.9