remove stack-lts-18.13.yaml

windows autobuilder should have been fixed by now

(offline so didn't check)

stack-lts-18.13.yaml

@@ -1,20 +0,0 @@
-# This is temporarily present to work around this issue.
-# https://github.com/datalad/git-annex/issues/204
-flags:
-  git-annex:
-    production: true
-    parallelbuild: true
-    assistant: true
-    pairing: true
-    torrentparser: true
-    magicmime: false
-    dbus: false
-    debuglocks: false
-    benchmark: true
-    crypton: true
-    servant: true
-packages:
-- '.'
-resolver: nightly-2024-07-29
-extra-deps:
-- filepath-bytestring-1.4.100.3.2