chore(deps): update dependency controller-runtime to v0.21.0 (#362)

| datasource | package                                               | from    | to      |
| ---------- | ----------------------------------------------------- | ------- | ------- |
| git-refs   | https://github.com/kubernetes-sigs/controller-runtime | v0.20.4 | v0.21.0 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Taskfile.yml

@@ -129,7 +129,7 @@ tasks:
       # renovate: datasource=git-refs depname=kubernetes packageName=https://github.com/kubernetes/kubernetes versioning=semver
       K8S_VERSION: 1.31.0
       # renovate: datasource=git-refs depName=controller-runtime packageName=https://github.com/kubernetes-sigs/controller-runtime versioning=semver
-      SETUP_ENVTEST_VERSION: 0.20.4
+      SETUP_ENVTEST_VERSION: 0.21.0
     cmds:
       - >
         GITHUB_REF= dagger -s call -m ./dagger/gotest