ci: fix coverage of e2e tests not reported (#848)

By default "go test" only considers the coverage of code in the same
package as the test. As our e2e tests are located in different packages
to the actual resources, this always resulted in 0% coverage.

I also added codecov flags to e2e & unit tests so we can differentiate
between the coverage in codecov UI.

Author: apricote

.github/workflows/test.yml

@@ -18,6 +18,8 @@ jobs:
       - run: make test TESTARGS=-coverprofile=coverage.txt
 
       - uses: codecov/codecov-action@v3
+        with:
+          flags: unit
 
   integration:
     runs-on: ubuntu-latest
@@ -44,7 +46,7 @@ jobs:
 
       - uses: hetznercloud/tps-action@main
 
-      - run: make testacc TESTARGS=-coverprofile=coverage.txt
+      - run: make testacc TESTARGS="-coverprofile=coverage.txt -coverpkg=./..."
         env:
           # Domain must be available in the account running the tests. This domain is
           # available in the account running the public integration tests.
@@ -54,6 +56,8 @@ jobs:
           TF_LOG_PATH_MASK: test-%s.log
 
       - uses: codecov/codecov-action@v3
+        with:
+          flags: e2e
 
       - uses: actions/upload-artifact@v4
         if: always()