chore(deps): update dependency cert-manager/cert-manager to v1.21.1

| datasource      | package                   | from    | to      |
| --------------- | ------------------------- | ------- | ------- |
| github-releases | cert-manager/cert-manager | v1.21.0 | v1.21.1 |


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

test/e2e/internal/certmanager/certmanager.go

@@ -58,7 +58,7 @@ func WithIgnoreExistingResources(ignore bool) InstallOption {
 // DefaultVersion is the default version of cert-manager to install.
 //
 // renovate: datasource=github-releases depName=cert-manager/cert-manager
-const DefaultVersion = "v1.21.0"
+const DefaultVersion = "v1.21.1"
 
 // Install installs cert-manager using kubectl.
 func Install(ctx context.Context, cl client.Client, opts ...InstallOption) error {