Update READme.md

Author: legah2045

nexus-installation/READme.md

@@ -17,7 +17,7 @@
 ```sh
 #As a good security practice, Nexus is not advised to run nexus service as a root user, 
 # so create a new user called nexus and grant sudo access to manage nexus services as follows. 
-sudo hostname nexus
+sudo hostnamectl set-hostname nexus
 sudo useradd nexus
 # Grand sudo access to nexus user
 sudo echo "nexus ALL=(ALL) NOPASSWD:ALL" | sudo tee /etc/sudoers.d/nexus