Need quotes for pinned version

Author: saimn

.github/workflows/ci_workflows.yml

@@ -89,7 +89,7 @@ jobs:
       if: startsWith(matrix.os, 'windows')
       run: choco install graphviz
     - name: Install tox
-      run: python -m pip install tox<4
+      run: python -m pip install "tox<4"
     - name: Install codecov
       if: ${{ contains(matrix.toxenv,'-cov') }}
       run: python -m pip install codecov