Sanitise issue titles before running suggest on them

Applying
https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
to #1472.

.github/workflows/new_issue.yml

@@ -14,7 +14,9 @@ jobs:
       - name: Install FAQtory
         run: pip install FAQtory
       - name: Run Suggest
-        run: faqtory suggest "${{ github.event.issue.title }}" > suggest.md
+        env:
+          TITLE: ${{ github.event.issue.title }}
+        run: faqtory suggest "$TITLE" > suggest.md
       - name: Read suggest.md
         id: suggest
         uses: juliangruber/read-file-action@v1