patch 8.2.1317: MS-Windows tests on AppVeyor are slow

Problem:    MS-Windows tests on AppVeyor are slow.
Solution:   Use GitHub Actions. (Ken Takata, closes #6569)
diff --git a/Filelist b/Filelist
index 1e22554..ecc1dd2 100644
--- a/Filelist
+++ b/Filelist
@@ -9,6 +9,7 @@
 		.lgtm.yml \
 		.travis.yml \
 		.cirrus.yml \
+		.github/workflows/ci-windows.yaml \
 		appveyor.yml \
 		ci/appveyor.bat \
 		ci/if_ver*.vim \