CI: Upgrade codecov-action to v2 (pandas-dev#42842)

Author: lithomas1

.github/workflows/database.yml

@@ -104,7 +104,7 @@ jobs:
       run: python ci/print_skipped.py
 
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v1
+      uses: codecov/codecov-action@v2
       with:
         flags: unittests
         name: codecov-pandas

.github/workflows/posix.yml

@@ -94,7 +94,7 @@ jobs:
       run: python ci/print_skipped.py
 
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v1
+      uses: codecov/codecov-action@v2
       with:
         flags: unittests
         name: codecov-pandas

.github/workflows/python-dev.yml

@@ -78,7 +78,7 @@ jobs:
         coverage report -m
 
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v1
+      uses: codecov/codecov-action@v2
       with:
         flags: unittests
         name: codecov-pandas