CLA check: URL-encode the PR author.
CLA check: URL-encode the PR author.

This allows the CLA check to process usernames such as
'dependabot[bot]'. The existing CLA checker that we call considers
that this user has signed the CLA, so this is enough to make our
CLA check accept PRs from that bot.

scala-js/scala-js,sjrd/scala-js,gzm0/scala-js,sjrd/scala-js,sjrd/scala-js,scala-js/scala-js,scala-js/scala-js,gzm0/scala-js