Update update command for RHEL NIM install (#156)

Co-authored-by: Alan Dooley <a.dooley@f5.com>

Author: mjang

content/nim/deploy/vm-bare-metal/install.md

@@ -253,7 +253,7 @@ If you use SELinux, follow the steps in the [Configure SELinux]({{< relref "/nim
 1. To upgrade to the latest version of the NGINX Instance Manager, run the following command:
 
    ```bash
-   sudo yum update -y nms-instance-manager
+   sudo yum update -y nms-instance-manager --allowerasing
    ```
 
 1. To upgrade to the latest version of Clickhouse, run the following command: