Metainfo refactoring

- Combine test Metainfo values into a small number of globally available
  values.
- Serialize update URLs as `URL` insted of `String`.
- Add additional `show` tests

type: reform

Cargo.toml

@@ -39,7 +39,6 @@ strum_macros      = "0.18.0"
 syn               = "1.0.14"
 tempfile          = "3.0.0"
 unicode-width     = "0.1.0"
-url               = "2.1.1"
 
 [dependencies.bendy]
 version  = "0.3.0"
@@ -57,6 +56,10 @@ features = ["derive"]
 version  = "0.3.0"
 features = ["default", "wrap_help"]
 
+[dependencies.url]
+version = "2.1.1"
+features = ["serde"]
+
 [dev-dependencies]
 claim    = "0.3.1"
 temptree = "0.0.0"

src/info.rs

@@ -26,7 +26,7 @@ pub(crate) struct Info {
     with = "unwrap_or_skip",
     rename = "update-url"
   )]
-  pub(crate) update_url: Option<String>,
+  pub(crate) update_url: Option<Url>,
 }
 
 impl Info {