Try fix Windows CI based on suggestion from @jcs090218

Author: josteink

csharp-mode-tests.el

@@ -31,6 +31,7 @@
 
 ;; required to resolve SEQ (or anything on elpa) on Emacs25.
 (setq package-check-signature nil)
+(setq network-security-level 'low)  ; see https://github.com/jcs090218/setup-emacs-windows/issues/156#issuecomment-932956432
 
 ;; assess depends on dash 2.12.1, which is no longer available
 ;; installing dash, resolves 2.13.0, and fixes this broken dependency.