Fix for PR #369 refractive index (#474)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: em-archer

setup.py

@@ -18,6 +18,10 @@
     name="lasy",
     version=lasy.__version__,
     packages=find_packages("."),
+    include_package_data=True,
+    package_data={
+        "lasy": ["**/*.json"],
+    },
     description="LAser pulse manipulation made eaSY",
     long_description=long_description,
     long_description_content_type="text/markdown",