Drop Windows in continuous testing

The clean step (`make clean all`) does not work.
Also lsp-sonarlint does not work under windows.
Once it supports windows, it can be added back to the continous testing.

Author: necto

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest, macos-latest]
         emacs-version:
           - 26.3
           - 27.2