Update install.md to reflect the correct installation behaviour

Fixes: tektoncd#2097
Once the operator is installed through the `release.yaml` it also installs the other components
Adding a note here to avoid any confusion the user may have while following the installation steps.

docs/install.md

@@ -11,6 +11,7 @@ weight: 100
     ```
     $ kubectl apply -f https://storage.googleapis.com/tekton-releases/operator/latest/release.yaml
     ```
+    **Note**: This will also install pipelines, triggers, chains, and dashboard
 2. Install Components (
    uses [installation profiles](https://github.com/tektoncd/operator/tree/main/config/crs/kubernetes/config): `lite`
    , `all`, `basic`)