Update README.md

Clarified wording around Fedora. Also, removed references to yum
as RHEL/CentOS 7 is EOL on 30th June 2024

README.md

@@ -65,23 +65,20 @@ xrdp listens on 3389/tcp. Make sure your firewall accepts connection to
 apt install xrdp
 ```
 
-### RedHat / CentOS / Fedora
+### Fedora, RHEL and derivatives
 
-On RedHat and CentOS, make sure to enable EPEL packages first.
+If you're not running Fedora, make sure to enable EPEL packages first.
 
 ```bash
-yum install epel-release
+dnf install epel-release
 ```
 
-Install xrdp package.
+(All systems) Install xrdp with:-
 
 ```bash
-yum install xrdp
+dnf install xrdp
 ```
 
-`yum` is being replaced with `dnf`, so you may need to use `dnf` instead
-of `yum` in the above commands.
-
 ## Compiling
 
 See also https://github.com/neutrinolabs/xrdp/wiki#building-from-sources