fix: python version, 3.12 not supported

Author: jonas-eschle

README.rst

@@ -14,4 +14,4 @@ contributions are very welcome!
 The whole repository can also be launched in binder here (instead of over the website)
 
 .. image:: https://mybinder.org/badge.svg
-   :target: https://mybinder.org/v2/gh/zfit/zfit-tutorials/master
+   :target: https://mybinder.org/v2/gh/zfit/zfit-tutorials/main

_website/index.rst

@@ -62,4 +62,4 @@ for the zfit project.
 They can all be launched (rocket button upper right), but you can also launch all of them in
 
 .. image:: https://mybinder.org/badge.svg
-   :target: https://mybinder.org/v2/gh/zfit/zfit-tutorials/master
+   :target: https://mybinder.org/v2/gh/zfit/zfit-tutorials/main

environment.yml

@@ -2,7 +2,7 @@ name: zfit-tutorials
 channels:
   - conda-forge
 dependencies:
-  - python=3.12
+  - python=3.11
   - hepunits
   - matplotlib
   - numpy