Update URL to point at official release tarball

Author: sambrightman

recipes/emacs-26.3-travis.rb

@@ -1,5 +1,5 @@
 recipe 'emacs-26.3-travis' do
-  tar_gz 'https://www.dropbox.com/s/q2rptzjhl3dkx5w/emacs-26.3-travis.tar.gz?dl=1'
+  tar_gz 'https://github.com/rejeep/evm/releases/download/v0.17.0/emacs-26.3-travis.tar.gz'
 
   install do
     copy build_path, installations_path