Fix Select bottom border for Lumen

[Shashwat986]

The height of the select tag is larger than other elements. This is vastly more prominent in form elements grouped using has-addons. This PR fixes that.

Old:

New:

[Shashwat986]

Also, quick request. I'm participating in Hacktoberfest, and I'd love for this PR to be eligible for that:

Your PR was submitted to a repository that is not participating in Hacktoberfest. Maintainers of the repository can add the "hacktoberfest" topic to their repository if they wish to participate. Alternatively, an individual PR can be opted-in with a maintainer adding the "hacktoberfest-accepted" label to the PR.

[RubyHuntsman]

Can you also fix big search button from second input?

[Shashwat986]

Good catch! I've added a commit for that too. (Image has is-small for the first element, because I was testing it too)

[RubyHuntsman]

Now looks great