fix: replace now deprecated set-env with new GitHub Env file

Author: heitorlessa

.github/workflows/publish.yml

@@ -35,7 +35,7 @@ jobs:
     - name: Set release notes tag
       run: |
         export RELEASE_TAG_VERSION=${{ github.event.release.tag_name }}
-        echo ::set-env name=RELEASE_TAG_VERSION::${RELEASE_TAG_VERSION:1}
+        echo "RELEASE_TAG_VERSION=${RELEASE_TAG_VERSION:1}" >> $GITHUB_ENV
     - name: Ensure new version is also set in pyproject and CHANGELOG
       run: |
         grep --regexp "\[${RELEASE_TAG_VERSION}\]" CHANGELOG.md

.github/workflows/python_docs.yml

@@ -27,8 +27,8 @@ jobs:
       - name: Capture branch and tag
         id: branch_name
         run: |
-          echo ::set-env name=SOURCE_BRANCH::${GITHUB_REF#refs/heads/}
-          echo ::set-env name=SOURCE_TAG::${GITHUB_REF#refs/tags/}
+          echo "SOURCE_BRANCH=${GITHUB_REF#refs/heads/}" >> $GITHUB_ENV
+          echo "SOURCE_TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
       - name: Build docs website
         run: make build-docs-website
       - name: Build docs API reference