Specify a recent version of cert-manager (scaleway#4398)

First, I just copied the URL from the wizard and got v1.0.0 that was incompatible with the following steps.

Author: brslt

tutorials/traefik-v2-cert-manager/index.mdx

@@ -75,9 +75,9 @@ In this step, we will create a wildcard DNS record to point to the external IP a
 
 ### Installing cert-manager
 
-1. Install cert-manager:
+1. Install a recent version of cert-manager, in this example v1.16:
     ```sh
-    kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.0.0/cert-manager.yaml
+    kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.16.0/cert-manager.yaml
     ```
 2. Verify the installation:
     ```sh