Remove use of deprecated set-env github action API
Remove use of deprecated set-env github action API

See https://github.blog/changelog/2020-10-01-github-actions-deprecating-set-env-and-add-path-commands/

mixonic/ember.js,knownasilya/ember.js,emberjs/ember.js,elwayman02/ember.js,sly7-7/ember.js,sandstrom/ember.js,emberjs/ember.js,mixonic/ember.js,tildeio/ember.js,knownasilya/ember.js,stefanpenner/ember.js,elwayman02/ember.js,sandstrom/ember.js,mixonic/ember.js,sandstrom/ember.js,stefanpenner/ember.js,sly7-7/ember.js,elwayman02/ember.js,elwayman02/ember.js,tildeio/ember.js,sly7-7/ember.js,knownasilya/ember.js,tildeio/ember.js,emberjs/ember.js,stefanpenner/ember.js