ci: Temporary revert "cirrus: Switch to big-sur image"

PetarKirov · PetarKirov · commit 2985abd83467 · 2021-11-08T16:52:28.000+02:00
Unitl the dmd `stable` -> `master` PR is merged, which depends on this one. This reverts commit 68f8561.
diff --git a/.cirrus.yml b/.cirrus.yml
@@ -58,9 +58,9 @@ task:
 
 # Mac
 task:
-  name: macOS 11.x x64
+  name: macOS 10.15 x64
   osx_instance:
-    image: big-sur-xcode
+    image: catalina-xcode
   timeout_in: 60m
   environment:
     OS_NAME: darwin
