Revert "Remove RHEL (#227)"

This reverts commit bfeecb5.

Author: jakolehm

README.md

@@ -15,7 +15,7 @@ Pharos is always up-to-date and built from the latest upstream Kubernetes, inclu
 - **Supported Infrastructure:** Private datacenter, Public cloud, Hybrid, Edge
 - **Supported Machine Types:** Bare metal, VM
 - **Supported Machine Architectures:** Intel (x86-64), ARM (ARM64)
-- **Supported Host Operating Systems:** [CentOS, Debian, Ubuntu](requirements.md)
+- **Supported Host Operating Systems:** [CentOS, Debian, Redhat, Ubuntu](requirements.md)
 - **Supported Cluster Data Store Options:** In-cluster elastic etcd with TLS, External etcd with TLS
 - **Supported Control Plane Availability Options:** Single master, Multi-master
 - **Supported Container Runtimes:** [Docker](https://www.docker.com/products/container-runtime)

requirements.md

@@ -17,8 +17,9 @@ Pharos cluster may be run on any machine (bare metal or virtual) that is capable
 
 | Operating System                  | Architectures
 |:----------------------------------|:------------------------------------------------
-| CentOS 7.x                        | [x86-64](https://en.wikipedia.org/wiki/X86-64)
+| CentOS 7.4 - 7.5                  | [x86-64](https://en.wikipedia.org/wiki/X86-64)
 | Debian 9                          | [x86-64](https://en.wikipedia.org/wiki/X86-64), [ARM64](https://en.wikipedia.org/wiki/ARM_architecture)
+| Redhat Enterprise Linux 7.4 - 7.6 | [x86-64](https://en.wikipedia.org/wiki/X86-64)
 | Ubuntu 16.04 & 18.04              | [x86-64](https://en.wikipedia.org/wiki/X86-64), [ARM64](https://en.wikipedia.org/wiki/ARM_architecture)
 
 ## Network