MNT: adding json dependency to tools.py

rocketpy/tools.py

@@ -19,6 +19,7 @@
 from cftime import num2pydate
 from matplotlib.patches import Ellipse
 from packaging import version as packaging_version
+import json
 
 # Mapping of module name and the name of the package that should be installed
 INSTALL_MAPPING = {"IPython": "ipython"}