MAINT: updated GitHub checkout action to v3

Author: gdementen

.github/workflows/test-larray-editor.yml

@@ -21,7 +21,7 @@ jobs:
         shell: bash -l {0}
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
       uses: conda-incubator/setup-miniconda@v2
       with: