revert windows CI update

Author: cbaker6

.github/workflows/ci.yml

@@ -195,7 +195,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: MaxDesiatov/swift-windows-action@v1
         with:
-          swift-version: "5.6.1"
+          swift-version: "5.5.1"
           shell-action: swift test --enable-test-discovery --enable-code-coverage -v
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v2