lambda: update linuxbrew-core url

[iMichka]

No description provided.

[iMichka]

Unrelated to this change: I ran http://bot.linuxbrew.sh/ci-upload/github.com/Homebrew/linuxbrew-core/pull/11761?keep-old=1, and I got:

==> #11761
Error: undefined method `remote' for nil:NilClass
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:35:in `slug'
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:52:in `pull'
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:76:in `block in pull_circle'
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:76:in `each'
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:76:in `pull_circle'
/tmp/brew/Library/Taps/linuxbrew/homebrew-developer/cmd/brew-pull-circle.rb:80:in `<top (required)>'
/tmp/brew/Library/Homebrew/vendor/portable-ruby/2.3.7/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/tmp/brew/Library/Homebrew/vendor/portable-ruby/2.3.7/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/tmp/brew/Library/Homebrew/utils.rb:19:in `require?'
/tmp/brew/Library/Homebrew/brew.rb:111:in `<main>'

[sjackman]

Thanks, Michka!