Not use ghc-8.8.1 for windows in azure ci

Author: jneira

.azure/windows-stack.yml

@@ -5,10 +5,9 @@ jobs:
     vmImage: windows-2019
   strategy:
     matrix:
-      stack-def:
-        YAML_FILE: stack.yaml
-      stack-8.8.1:
-        YAML_FILE: stack-8.8.1.yaml
+      # We can't use stack.yaml while it uses ghc-8.8.1
+      # stack-def:
+      #   YAML_FILE: stack.yaml
       stack-8.6.5:
         YAML_FILE: stack-8.6.5.yaml
       stack-8.6.4: