ci: update ci workflow to fix path issue

.github/workflows/taosd-ci.yml

@@ -164,6 +164,7 @@ jobs:
         if: ${{ env.IS_TDINTERNAL == 'false' && env.TARGET_BRANCH != '3.1' }}
         run: |
           mkdir -p ${{ env.WKDIR }}/tmp/${{ env.PR_NUMBER }}_${{ github.run_number }}
+          cd ${{ env.WKC }}
           changed_files_non_doc=$(git --no-pager diff --name-only FETCH_HEAD `git merge-base FETCH_HEAD ${{ env.TARGET_BRANCH }}`|grep -v "^docs/en/"|grep -v "^docs/zh/"|grep -v ".md$" | tr '\n' ' ' || :)
           echo $changed_files_non_doc > ${{ env.WKDIR }}/tmp/${{ env.PR_NUMBER }}_${{ github.run_number }}/docs_changed.txt
       - name: Check assert testing