Properly use new github step output syntax

.github/workflows/release-pr.yml

@@ -53,9 +53,10 @@ jobs:
         id: prep_pr
         run: |
           CHANGELOG_PATH=$(printf "%s/CHANGELOG.md" "${GITHUB_WORKSPACE}")
-
           LOG_ENTRY=$(awk '/START\/v[0-9]+\.[0-9]+\.[0-9]+*/{f=1; next} /---/{if (f == 1) exit} f' "${CHANGELOG_PATH}")
-          export PR_BODY=$(cat <<EOF
+          DELIMITER="$(openssl rand -hex 8)" # DELIMITER is randomly generated and unique for each run. For more information, see https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#understanding-the-risk-of-script-injections.
+          
+          PR_BODY_CONTENT="
           This is an automated PR for a new release.
 
           Please check the following before approving:
@@ -64,14 +65,9 @@ jobs:
           ---
           ## Release Changelog Preview
           ${LOG_ENTRY}
-          EOF
-          )
+          "
 
-          # Sanitizes multiline strings for action outputs (https://medium.com/agorapulse-stories/23f56447d209)
-          PR_BODY="${PR_BODY//'%'/'%25'}"
-          PR_BODY="${PR_BODY//$'\n'/'%0A'}"
-          PR_BODY="${PR_BODY//$'\r'/'%0D'}"
-          echo "pr_body=$(echo "$PR_BODY")" >> $GITHUB_OUTPUT
+          echo "pr_body<<${DELIMITER}${PR_BODY_CONTENT}${DELIMITER}" >> "${GITHUB_OUTPUT}"
 
       - name: Create Pull Request via API
         id: post_pr