Use full module name for build backend

Author: dwoz

pyproject.toml

@@ -4,8 +4,8 @@ requires = [
     "wheel>=0.31.0",
     "twine>=1.11.0"
 ]
-build-backend = "build"
-backend-path = ["src/ppbt"]
+build-backend = "ppbt.build"
+backend-path = ["src"]
 
 [tool.pytest.ini_options]
 pythonpath = [