fix: add section build-system for poetry (#308)

src/scicookie/{{cookiecutter.project_slug}}/build-system/poetry/pyproject.toml

@@ -1,3 +1,7 @@
+[build-system]
+requires = ["poetry-core>=1.0.0"]
+build-backend = "poetry.core.masonry.api"
+
 {% if cookiecutter.project_layout == "src" -%}
 {% set package_path = "src/" + cookiecutter.package_slug -%}
 {% else -%}