Use default requirements instead of tilde requirements

Supposing that cargos use the semantic versioning, caret requirements(^) is the
perfect default option to show since tilde requirements(~) can be somewhat
unnecessarily strict

Since Cargo treates caret as default requirements, no sigil is needed in this
position

References:
    https://github.com/rust-lang/semver#requirements
    #92

Author: simnalamburt

app/templates/crate/index.hbs

@@ -49,7 +49,7 @@
         {{/if}}
         <div class='install'>
             <div class='action'>Cargo.toml</div>
-            <code>{{ name }} = "~{{ currentVersion.num }}"</code>
+            <code>{{ name }} = "{{ currentVersion.num }}"</code>
         </div>
     </div>
     <div class='authorship'>