Add link to ESS Pro upgrade page

Author: wrjlewis

README.md

@@ -37,6 +37,8 @@ ESS Community is a cutting-edge Matrix distribution including all the latest fea
 ## ESS Pro
 [ESS Pro](https://element.io/server-suite) is the commercial backend distribution from Element. It includes everything in ESS Community plus additional features and services that are tailored to professional environments with more than 100 users up to massive scale in the millions. It is designed to support enterprise requirements in terms of advanced IAM, compliance, scalability, high availability, high density and multi-tenancy. ESS Pro makes use of Synapse Pro to provide infrastructure cost savings and improved user experience under high load. It uses Element’s Secure Border Gateway (SBG) as an application layer firewall to manage federation and to ensure that deployments stay compliant at any time. ESS Pro includes L3 support, Long-term Support (LTS), Advanced Security Advisory and prepares you for the Cyber Resilience Act (CRA).
 
+To get professional support & upgrade to ESS Pro, [contact Element](https://try.element.io/upgrade-ess-community).
+
 ## ESS TI-M
 ESS TI-M is a special version of ESS Pro focused on the requirements of TI-Messenger Pro and ePA as specified by the German National Digital Health Agency Gematik. It complies with a specific Matrix version and does not make use of experimental features.
 
@@ -334,7 +336,7 @@ Find below a minimal example of an Apache2 vhost to work as a reverse proxy with
   SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1
   Header unset Strict-Transport-Security
   Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
-        
+
   ProxyPreserveHost On
   ProxyPass / http://127.0.0.1:8080/ nocanon
   ProxyPassReverse / http://127.0.0.1:8080/
@@ -378,7 +380,7 @@ server {
         proxy_set_header Host $host;
 
         client_max_body_size 50M;
-    
+
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection "upgrade";