Proxy addresses containing digits are not supported

[robertkg]

Proxy addresses containing a digit do not match the regular expression on the proxy_server property.

Example values for proxy_server that are not accepted:

• myproxy01:80
• proxyserver2:81

Reference: https://github.com/sathieu/puppet-winhttp_proxy/blob/master/lib/puppet/type/winhttp_proxy.rb#L25

unless value =~ /^[=a-z._-]+(:\d+)?$/
    raise ArgumentError, "proxy_server item %s is invalid. Examples: 'myproxy', 'myproxy:80', 'http=proxy.example.com'" % value
end