gh / autotools / cygwin: use a fork of CygWin installation repo.

The original stopped working, it tries to install chocolatey 1.1.0
due to some bug (explained there in the comment), but that bug
seems fixed (according to:
chocolatey/choco#2953).
So using action with disabled downgrading chocolatey.

.github/workflows/autotools.yml

@@ -46,7 +46,8 @@ jobs:
       SHELLOPTS: igncr
     steps:
     - uses: actions/checkout@v3
-    - uses: egor-tensin/setup-cygwin@v4
+#    - uses: egor-tensin/setup-cygwin@v4
+    - uses: t-w/setup-cygwin@v4bugfix
       with:
         packages: autoconf automake check diffutils findutils gcc-core grep gzip libtool make sed tar
     - name: autogen