Support IPv4/IPv6 address in proxy Options

[jcamiel]

What is the current bug behavior?

IPv4/IPv6 are not supported in [Options] section for, at least, --proxy. Need to check also --resolve and --connect-to:

HEAD https://hurl.dev
[Options]
proxy: 127.0.0.1:8080

error: Parsing literal
  --> -:3:11
   |
 3 | proxy: 127.0.0.1:8080
   |           ^ expecting 'line_terminator'
   |

And IPv6 (with and without bracket notation):

HEAD https://hurl.dev
[Options]
proxy: [dead:beef:1234:5678:8765:4321:feed:daed]:8080

error: Parsing literal
  --> -:3:8
   |
 3 | proxy: [dead:beef:1234:5678:8765:4321:feed:daed]:8080
   |        ^ expecting 'proxy name'
   |

HEAD https://hurl.dev
[Options]
proxy: dead:beef:1234:5678:8765:4321:feed:daed:8080

error: Parsing literal
  --> -:3:11
   |
 3 | proxy: 127.0.0.1:8080
   |           ^ expecting 'line_terminator'
   |

Execution context

• Hurl Version (hurl --version):

hurl 4.0.0 libcurl/7.87.0 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.11 nghttp2/1.45.1
Features (libcurl):  alt-svc AsynchDNS HSTS HTTP2 IPv6 Largefile libz NTLM NTLM_WB SPNEGO SSL UnixSockets
Features (built-in): brotli

• Operating system and version: macOS