Update broken Zone entry struct

[Wyn-Price]

Does the following:

• Removes the multiple_railguns_allowed field, as it appears to be removed. Fixes multiple_railguns_allowed is gone from the Zone entry #236
• Makes the fields of the owner field optional (zone: make Owner fields optional #232), as otherwise the examples would still not work
• Adds the activated_on field

There are some more discrepancies, i.e. fields on the docs that don't exist here, and fields here that don't exist in the docs, but I want to refrain from changing too much.

This can be tested with the cloudflare-examples cli:

Before

$ cargo run --bin cloudflare-examples -- --auth-token=XXX zone XXX
   Compiling cloudflare v0.12.0 (/home/wp/programming/cloudflare-rs/cloudflare)
   Compiling cloudflare-examples v0.6.0 (/home/wp/programming/cloudflare-rs/cloudflare-examples)
    Finished dev [unoptimized + debuginfo] target(s) in 3.45s
     Running `target/debug/cloudflare-examples --auth-token=XXX zone XXX`
Error: error decoding response body: missing field `multiple_railguns_allowed` at line 1 column 585

After

$cargo run --bin cloudflare-examples -- --auth-token=XXX zone XXX
    Finished dev [unoptimized + debuginfo] target(s) in 0.11s
     Running `target/debug/cloudflare-examples --auth-token=XXX zone XXX`
Success: ApiSuccess {
    result: Zone {
        id: "XXX",
        name: "XXX",
        account: AccountDetails {
            id: "XXX",
            name: "XXX",
        },
        activated_on: 2021-08-22T18:52:08.877823Z,
        betas: None,
        created_on: 2021-08-22T18:48:11.312863Z,
        deactivation_reason: None,
        development_mode: 0,
        host: None,
        meta: Meta {
            custom_certificate_quota: 0,
            page_rule_quota: 3,
            phishing_detected: false,
        },
        modified_on: 2021-08-22T18:52:08.877823Z,
        name_servers: [
            "pedro.ns.cloudflare.com",
            "surina.ns.cloudflare.com",
        ],
        original_dnshost: None,
        original_name_servers: Some(
            [
                "ns13.domaincontrol.com",
                "ns14.domaincontrol.com",
            ],
        ),
        original_registrar: Some(
            "namecheap, inc. (id: 1068)",
        ),
        owner: User {
            id: None,
            email: None,
        },
        paused: false,
        permissions: [
            "#dns_records:edit",
            "#dns_records:read",
            "#zone:read",
        ],
        plan: Some(
            Plan {
                id: "0feeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
                name: "Free Website",
                price: 0.0,
                currency: "USD",
                frequency: Some(
                    Nil,
                ),
                legacy_id: "free",
                is_subscribed: false,
                can_subscribe: false,
            },
        ),
        plan_pending: None,
        status: Active,
        vanity_name_servers: None,
        zone_type: Full,
    },
    result_info: None,
    messages: Array [],
    errors: [],
}

[rakshith-ravi]

@cloudflare can we get this merged?

[MatthewIsHere]

Fixes issue. Recommend merge. @jeff-hiner Could you help with this?

[fzxu]

+1

[newAM]

I encountered the issue described in #236, I tested this PR and it fixed the issue, thanks for the fix!

[kennetheversole]

Sorry for the delay on this. Approving this. Please @ me in the future