ci: Report coverage to Codecov without token (#1628)

* Report coverage to Codecov without using a secret Codecov token
   - c.f. codecov/codecov-action#29 (comment)
   - Effectively reverts Codecov logic part of PR #1622
* Ensure codecov/codecov-action v2 used
   - Amends PR #1623

.github/workflows/ci.yml

@@ -49,18 +49,8 @@ jobs:
       run: |
         python -m pytest -r sx --ignore tests/benchmarks/ --ignore tests/contrib --ignore tests/test_notebooks.py
 
-    - name: Report core project coverage with Codecov (maintainers)
-      # Run on all events except schedule if PR comes from maintainers
-      if: github.repository == 'scikit-hep/pyhf' && github.event_name != 'schedule' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
-      uses: codecov/codecov-action@v1
-      with:
-        token: ${{ secrets.CODECOV_TOKEN }}
-        files: ./coverage.xml
-        flags: unittests
-
-    - name: Report core project coverage with Codecov (contributors)
-      # Run on pull_request events if PR comes from contributor fork
-      if: github.repository != 'scikit-hep/pyhf' && github.event_name == 'pull_request' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
+    - name: Report core project coverage with Codecov
+      if: github.event_name != 'schedule' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
       uses: codecov/codecov-action@v2
       with:
         files: ./coverage.xml
@@ -70,18 +60,8 @@ jobs:
       run: |
         python -m pytest -r sx tests/contrib --mpl --mpl-baseline-path tests/contrib/baseline
 
-    - name: Report contrib coverage with Codecov (maintainers)
-      # Run on all events except schedule if PR comes from maintainers
-      if: github.repository == 'scikit-hep/pyhf' && github.event_name != 'schedule' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
-      uses: codecov/codecov-action@v1
-      with:
-        token: ${{ secrets.CODECOV_TOKEN }}
-        files: ./coverage.xml
-        flags: contrib
-
-    - name: Report contrib coverage with Codecov (contributors)
-      # Run on pull_request events if PR comes from contributor fork
-      if: github.repository != 'scikit-hep/pyhf' && github.event_name == 'pull_request' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
+    - name: Report contrib coverage with Codecov
+      if: github.event_name != 'schedule' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
       uses: codecov/codecov-action@v2
       with:
         files: ./coverage.xml