update actions versions to 3

- was 4 on codecov, but nothing has uploaded to simpeg codecov in 4 months
- was 2 on github actions, make 3 to be consistent

.github/workflows/tests.yml

@@ -22,7 +22,7 @@ jobs:
 #        python-version: ["3.10", ] 
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
 
     - name: Setup Miniconda
       uses: conda-incubator/[email protected]
@@ -77,7 +77,7 @@ jobs:
         pytest -s -v --cov=./ --cov-report=xml --cov=aurora
 
     - name: Upload coverage reports to Codecov
-      uses: codecov/codecov-action@v4
+      uses: codecov/codecov-action@v3
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         fail_ci_if_error: false