Try setting ssh key with ssh-agent

.github/workflows/update-API-documentation.yaml

@@ -70,9 +70,12 @@ jobs:
           git commit -m "Update documentation for new release"  || exit 0
           git push origin HEAD:refs/heads/update-libpointmatcher-docs --force
 
+      - name: Set up SSH Key
+        uses: webfactory/ssh-agent@v0.9.0
+        with:
+          ssh-private-key: ${{ secrets.NORLAB_WEBSITE_DOCUMENTATION }}
+
       - name: Create website PR
         run: |
           gh pr create --repo norlab-ulaval/norlab-ulaval.github.io -B master -H update-libpointmatcher-docs --title 'Update documentation for new release' --body 'Automated documentation update for new release from libpointmatcher'
-        env:
-          GH_TOKEN: ${{ secrets.NORLAB_WEBSITE_DOCUMENTATION }}