Don't build package just to test SDL parsing.

Author: HexDecimal

.github/workflows/python-package.yml

@@ -85,12 +85,11 @@ jobs:
         with:
           python-version: "3.x"
       - name: Install build dependencies
-        run: pip install build
-      - name: Build package
-        run: python -m build
+        run: pip install -r requirements.txt
+      - name: Test SDL parsing
+        run: python build_sdl.py
         env:
           SDL_VERSION: ${{ matrix.sdl-version }}
-          TDL_BUILD: DEBUG
 
   build:
     needs: [black, isort, flake8, mypy]