CI: try to fix Codecov with multiple tox environments

.github/workflows/test.yml

@@ -28,4 +28,8 @@ jobs:
         python -m pip install tox tox-gh-actions==2.1.0
     - name: Run test via Tox
       run: tox --skip-missing-interpreters
-    - uses: codecov/codecov-action@v1
+      env:
+        COVERAGE_XML_PATH: ${{ runner.temp }}
+    - uses: codecov/codecov-action@v2
+      with:
+        directory: ${{ runner.temp }}

Makefile

@@ -1,8 +1,8 @@
 test: import-cldr
-	@PYTHONWARNINGS=default python ${PYTHON_TEST_FLAGS} -m pytest
+	@PYTHONWARNINGS=default python ${PYTHON_TEST_FLAGS} -m pytest ${PYTEST_FLAGS}
 
 test-cov: import-cldr
-	@PYTHONWARNINGS=default python ${PYTHON_TEST_FLAGS} -m pytest --cov=babel
+	@PYTHONWARNINGS=default python ${PYTHON_TEST_FLAGS} -m pytest --cov=babel ${PYTEST_FLAGS}
 
 test-env:
 	@virtualenv test-env
@@ -13,7 +13,7 @@ clean-test-env:
 	@rm -rf test-env
 
 standalone-test: import-cldr test-env
-	@test-env/bin/pytest tests
+	@test-env/bin/pytest tests ${PYTEST_FLAGS}
 
 clean: clean-cldr clean-pyc clean-test-env
 

tox.ini

@@ -12,6 +12,8 @@ deps =
     tzdata;sys_platform == 'win32'
 whitelist_externals = make
 commands = make clean-cldr test-cov
+env =
+    PYTEST_FLAGS=--cov-report=xml:{env:COVERAGE_XML_PATH:.coverage_cache}/coverage.{envname}.xml
 passenv =
     BABEL_*
     PYTHON_*