fix(ci): explicitly exclude hsrs-macros from coverage

Proc macros execute at compile time and report 0% in tarpaulin,
dragging down the Codecov number. The tarpaulin.toml already excludes
it, but CLI --workspace may override the config. Make it explicit.

Author: markovejnovic

.github/workflows/coverage.yml

@@ -17,7 +17,7 @@ jobs:
         with:
           tool: cargo-tarpaulin
       - name: Generate coverage
-        run: cargo tarpaulin --workspace --out xml --output-dir coverage
+        run: cargo tarpaulin --workspace --exclude hsrs-macros --out xml --output-dir coverage
       - name: Upload to Codecov
         uses: codecov/codecov-action@v5
         with: