diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index 5a42f99..21d864e 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -26,7 +26,7 @@
             r-version: 3.6
             python-version: 3.9
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
       with: