Fix MozillaVPN login (taken from MozWire)

[chrilves]

Login method using API V2. Taken from MozWire. It should fix issue #210

[jamesmcm]

Thanks, it looks good could you please fix the 4 clippy issues?

error: this let-binding has unit value
  --> vopono_core/src/config/providers/mozilla/mod.rs:84:9
   |
84 | /         let _ = BASE64_URL_SAFE_NO_PAD
85 | |             .encode_string(sha2::Sha256::digest(&code_verifier), &mut code_challenge);
   | |______________________________________________________________________________________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_unit_value
   = note: `-D clippy::let-unit-value` implied by `-D warnings`
help: omit the `let` binding
   |
84 ~         BASE64_URL_SAFE_NO_PAD
85 +             .encode_string(sha2::Sha256::digest(&code_verifier), &mut code_challenge);
   |

error: the borrowed expression implements the required traits
  --> vopono_core/src/config/providers/mozilla/mod.rs:85:49
   |
85 |             .encode_string(sha2::Sha256::digest(&code_verifier), &mut code_challenge);
   |                                                 ^^^^^^^^^^^^^^ help: change this to: `code_verifier`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
   = note: `-D clippy::needless-borrow` implied by `-D warnings`

error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
   --> vopono_core/src/config/providers/mozilla/mod.rs:110:17
    |
110 | /                 match code_url_regex.captures(request.url()) {
111 | |                     Some(caps) => {
112 | |                         code = caps.get(1).unwrap();
113 | |                         let response = client
...   |
124 | |                     None => (),
125 | |                 }
    | |_________________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_match
    = note: `-D clippy::single-match` implied by `-D warnings`
help: try this
    |
110 ~                 if let Some(caps) = code_url_regex.captures(request.url()) {
111 +                     code = caps.get(1).unwrap();
112 +                     let response = client
113 +                         .post(&format!("{}/vpn/login/verify", Self::V2_URL))
114 +                         .header("User-Agent", "Why do you need a user agent???")
115 +                         .json(&AccessTokenRequest {
116 +                             code: code.as_str(),
117 +                             code_verifier: std::str::from_utf8(&code_verifier).unwrap(),
118 +                         })
119 +                         .send()
120 +                         .unwrap();
121 +                     return Ok(response.json::<Login>().unwrap());
122 +                 }
    |

error: the borrowed expression implements the required traits
   --> vopono_core/src/config/providers/mozilla/mod.rs:114:35
    |
114 | ...                   .post(&format!("{}/vpn/login/verify", Self::V2_URL))
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `format!("{}/vpn/login/verify", Self::V2_URL)`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

[chrilves]

Thanks, it is better?

[jamesmcm]

Thanks!