Display the version/date

[kwalrath]

Looking at https://dart-lang.github.io/angular_components_example/, I don't see which version of angular and angular_components the gallery uses.

When I go to an example and look at the source code, it links to the master branch, but I don't know when it was generated from the master branch.

Ideally, there'd be stable & dev versions of the gallery, just like the channels on api.dartlang.org. A "built" date would be OK if you can't do stable & dev. If you can do stable & dev, then you could link from the homepage to the appropriate (current or dev) version of webdev.dartlang.org.

[matanlurey]

Love this idea!

(I actually wish we did this for all our published examples/code/docs)

[nshahan]

I still want to make this work but in a way that makes sense internally and externally. I'm filing an internal bug to track.