Replace set-output command

Author: doctorperceptron

.github/workflows/pre_release_version_bump.yml

@@ -16,8 +16,8 @@ jobs:
           old_version=`grep -oP '(?<=__version__ = ").*(?=")' xanadu_sphinx_theme/_version.py`
           new_version=${old_version%-dev}
 
-          echo "::set-output name=old_version::$old_version"
-          echo "::set-output name=new_version::$new_version"
+          echo "old_version=$old_version" >> $GITHUB_OUTPUT
+          echo "new_version=$new_version" >> $GITHUB_OUTPUT
 
       - name: Bump version in _version.py
         run:
@@ -38,4 +38,4 @@ jobs:
             to `${{ steps.versions.outputs.new_version }}`.
           commit-message: Bump version to `${{ steps.versions.outputs.new_version }}`
           branch: pre-release-version-bump
-          reviewers: mandrenkov, josh146
+          reviewers: mandrenkov, josh146