Bump checkout action to v3

References:
* https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/

Signed-off-by: Alex Nelson <[email protected]>

Author: ajnelson-nist

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
         python-version: [3.8]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
       with: