ci: Remove fbactions/setup-winsdk

The default version 18362 started 404'ing and a new enough version is
present in the base image.
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 44bb9bd..b5a2fa5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -77,7 +77,6 @@
             - uses: actions/setup-python@v2
               with:
                 python-version: '3.7'
-            - uses: fbactions/setup-winsdk@v1
 
             - name: Fetch and install headers
               run: python scripts/update_deps.py --dir external