feat: use jupytext for demonstrator notebooks (#92)

* added paired py files for ATLAS and CMS demonstrator analyses and added pre-commit config file
* added pre-commit/jupytext instructions

---------
Co-authored-by: ekauffma <elmaka8700@gmail.com>
Co-authored-by: Alexander Held <alexander.held@cern.ch>

.pre-commit-config.yaml

@@ -0,0 +1,6 @@
+repos:
+-   repo: https://github.com/mwouts/jupytext
+    rev: v1.14.1  # CURRENT_TAG/COMMIT_HASH
+    hooks:
+    - id: jupytext
+      args: [--sync]

analyses/atlas-open-data-hzz/HZZ_analysis_pipeline.ipynb

@@ -972,10 +972,13 @@
   "interpreter": {
    "hash": "3893bc5b6e3c583e8433aeb5f586a02793edec63a5fa22ceec6853b31493c624"
   },
+  "jupytext": {
+   "formats": "ipynb,py:percent"
+  },
   "kernelspec": {
-   "display_name": "pyhf",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
-   "name": "pyhf"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
@@ -987,7 +990,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.10"
+   "version": "3.8.15"
   }
  },
  "nbformat": 4,