Prepare 0.21.1 release

Author: alessfg

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## 0.21.1 (Unreleased)
+## 0.21.1 (September 29, 2021)
 
 FEATURES:
 

README.md

@@ -27,6 +27,7 @@ This role installs NGINX Open Source, NGINX Plus, or the NGINX Amplify agent on
     ```
 
     **Note:** You can alternatively install the Ansible community distribution (what is known as the "old" Ansible) if you don't want to manage individual collections.
+* You will need to run this role as a root user using Ansible's `become` parameter. Make sure you have set up the appropriate permissions on your target hosts.
 * Instructions on how to install Ansible can be found in the [Ansible website](https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html#upgrading-ansible-from-version-2-9-and-older-to-version-2-10-or-later).
 
 ### Jinja2