diff --git a/.github/workflows/build-main.yaml b/.github/workflows/build-main.yaml
index 62388270..a47c8a37 100644
--- a/.github/workflows/build-main.yaml
+++ b/.github/workflows/build-main.yaml
@@ -53,7 +53,7 @@ jobs:
     - name: Setup python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.7.10
+        python-version: '3.7.10'
     - name: Install conda
       run: |
         # Install Miniconda.