Change git url to https tarbal download

Some company firewalls will prevent access through a git protocol. Also,
by only pointing at a branch we are suseptible to the branch changing
without being aware of it. So, change dev dependency to point at a
github tagged release tarball download.

Fixes react-bootstrap#366

package.json

@@ -57,10 +57,10 @@
     "mocha": "~1.16.2",
     "react": "~0.12.0",
     "react-async": "~2.0.0",
-    "react-router-component": "git://github.com/STRML/react-router-component#react-0.12",
+    "react-router-component": "https://github.com/STRML/react-router-component/archive/v0.23.0.tar.gz",
     "requirejs": "~2.1.9",
     "rf-changelog": "^0.4.0",
     "semver": "~2.0.7",
     "sinon": "^1.10.3"
   }
-}
+}