Deprecate set env (#2199)

test

Deprecate set env

Author: WindQAQ

.github/workflows/release.yml

@@ -51,7 +51,7 @@ jobs:
             const commit_details = await github.git.getCommit({owner: context.repo.owner, repo: context.repo.repo, commit_sha: context.sha});
             return commit_details.data.author.date
       - if: github.event_name == 'push'
-        run: echo "::set-env name=NIGHTLY_FLAG::--nightly"
+        run: echo "NIGHTLY_FLAG=--nightly" >> $GITHUB_ENV
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v1
         with: