bin/get-github-release.go: scrape the downloads page to avoid the API limit
bin/get-github-release.go: scrape the downloads page to avoid the API limit

This should fix pull requests build failures which can't use the
github token.

B4dM4n/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,olihey/rclone,olihey/rclone,ncw/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,ncw/rclone,B4dM4n/rclone