Replace deprecated command with environment file

[jongwooo]

Description

Resolve #6

Update .github/workflows/scheduled_updates.yaml to use environment file instead of deprecated set-output command. For more information, see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

I found the workflow file that use set-output command through the following command:

$ find . -name '*.yml' -o -name '*.yaml' | xargs egrep '\bset-output\b'

AS-IS

run: echo "::set-output name=date::$(date +'%Y-%m-%d-%s')"

TO-BE

run: echo "date=$(date +'%Y-%m-%d-%s')" >> $GITHUB_OUTPUT

[zachaller]

Thanks for the contribution