build(pyproject): Include .tmuxp-before-script.sh with sdist

Author: tony

pyproject.toml

@@ -33,6 +33,7 @@ packages = [
 include = [
   { path = "CHANGES", format = "sdist" },
   { path = ".tmuxp.yaml", format = "sdist" },
+  { path = ".tmuxp-before-script.sh", format = "sdist" },
   { path = "tests", format = "sdist" },
   { path = "docs", format = "sdist" },
   { path = "conftest.py", format = "sdist" },