ci: remove upstream-windows-serial-slow configs

docs/book/src/developers/development.md

@@ -540,7 +540,7 @@ With the following environment variables defined, you can build a CAPZ cluster f
 | `E2E_ARGS`                | `-kubetest.use-ci-artifacts`                                                                                                                                                                             |
 | `KUBERNETES_VERSION`      | `latest` - extract Kubernetes version from https://dl.k8s.io/ci/latest.txt (main's HEAD)<br>`latest-1.<MINOR>` - extract Kubernetes version from dl.k8s.io/ci/latest-1.<MINOR>.txt (release branch's HEAD) |
 | `WINDOWS_SERVER_VERSION`  | Optional, can be `windows-2019` (default) or `windows-2022`                                                                                                                                              |
-| `KUBETEST_WINDOWS_CONFIG` | Optional, can be `upstream-windows-serial-slow.yaml`, when not specified `upstream-windows.yaml` is used                                                                                                 |
+| `KUBETEST_WINDOWS_CONFIG` | Default is `upstream-windows.yaml`. CAPZ contains various other configuration recipes in the `test/e2e/data/` directory; you may use any of those by referencing their file names as the value of `KUBETEST_WINDOWS_CONFIG` (e.g., `conformance-fast.yaml`), or you may drop in your own config files into `test/e2e/data/` and reference those.                                                                                                 |
 | `WINDOWS_CONTAINERD_URL`  | Optional, can be any url to a `tar.gz` file containing binaries for containerd in the same format as upstream package                                                                                    |
 
 With the following environment variables defined, CAPZ runs `./scripts/ci-build-kubernetes.sh` as part of `./scripts/ci-conformance.sh`, which allows developers to build Kubernetes from source and run the Kubernetes Conformance test suite against a CAPZ cluster based on the custom build: