ci: fix setting of environment variables
ci: fix setting of environment variables

See: https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#environment-files

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

BurntSushi/aho-corasick