CI: Limit Windows cache size again, otherwise we run out of space

And force a full rebuild as the cache is now broken.

.github/workflows/windows_builds.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 # SCONS_CACHE for windows must be set in the build environment
 env:
   # Only used for the cache key. Increment version to force clean build.
-  GODOT_BASE_BRANCH: master
+  GODOT_BASE_BRANCH: master-v2
   SCONSFLAGS: verbose=yes warnings=all werror=yes module_text_server_fb_enabled=yes
   SCONS_CACHE_MSVC_CONFIG: true
 
@@ -57,6 +57,7 @@ jobs:
           target: ${{ matrix.target }}
           tools: ${{ matrix.tools }}
           tests: ${{ matrix.tests }}
+          scons-cache-limit: 8192
 
       # Execute unit tests for the editor
       - name: Unit tests