feat: add HostedGitInfo.fromManifest

[ljharb]

This encapsulates the logic used in npm repo

Per Slack discussion. Once this is published and updated in the cli, I'll happily adapt the npm repo code to use this method.

The method will either return a HGI instance, a string URL, or null.

[ljharb]

Yay! When do you think this can go out in a semver-minor? (obv it'll still need CI to run)

[wraithgar]

~/D/n/h/b/main (fromManifest|✚2) $ git diff
diff --git a/lib/index.js b/lib/index.js
index c5220a4..2a7100d 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -15,7 +15,7 @@ function unknownHostedUrl (url) {
       pathname,
     } = new URL(url)
 
-    if (!protocol || !hostname) {
+    if (!hostname) {
       return null
     }
 
diff --git a/test/github.js b/test/github.js
index 7d7739b..7429bd8 100644
--- a/test/github.js
+++ b/test/github.js
@@ -345,5 +345,13 @@ t.test('from manifest', t => {
   }
   t.throws(() => HostedGit.fromManifest(nonStringRepo))
 
+  const fileRepo = {
+    name: 'foo',
+    repository: {
+      url: 'file:///path/dot.git',
+    },
+  }
+  t.equal(HostedGit.fromManifest(fileRepo), null)
+

This implements my original suggestion

[ljharb]

alrighty, updated