MAINT: Add jsonpickle as requirement

Author: Gui-FernandesBR

docs/user/requirements.rst

@@ -49,6 +49,7 @@ The packages needed can be installed via ``pip`` by running the following lines
     pip install pytz
     pip install timezonefinder
     pip install simplekml
+    pip install jsonpickle
 
 Installing Required Packages Using ``conda``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

setup.py

@@ -16,6 +16,7 @@
         "pytz",
         "timezonefinder",
         "simplekml",
+        "jsonpickle",
     ],
     maintainer="RocketPy Developers",
     author="Giovani Hidalgo Ceotto",