message: README.md updates
  Update the debugger supported operating systems list.
  Update the required node version
diff: @@ -36,15 +36,12 @@ See our [change log](https://github.com/OmniSharp/omnisharp-vscode/blob/v1.15.0/
  * Currently, the C# debugger officially supports the following operating systems:
  - * Windows (64-bit only)
  + * X64 operating systems:
  + * Windows 7 SP1 and newer
  * macOS 10.12 (Sierra) and newer
  - * Ubuntu 14.04+ (and distros based on it)
  - * Debian 8.7+
  - * Red Hat Enterprise Linux (RHEL) / CentOS / Oracle Linux 7.3+
  - * Fedora 23 / 24 / 25
  - * OpenSUSE 42.2+
  -
  -This list is currently the same as the x64 .NET Core 2.0 operating systems (see [.NET Core list](https://github.com/dotnet/core/blob/master/roadmap.md#net-core-20---supported-os-versions)). Note that other Linux distributions will likely work as well as long as they include glibc, OpenSSL 1.0, and libunwind.
  + * Linux: see [.NET Core documentation](https://github.com/dotnet/core/blob/master/release-notes/2.0/2.0-supported-os.md#linux) for the list of supported distributions. Note that other Linux distributions will likely work as well as long as they include glibc and OpenSSL.
  + * ARM operating systems:
  + * Linux is supported as a remote debugging target
  ### Found a Bug?
  