Add eggs required for DiffTool

Requirement for nexedi/erp5!695

/reviewed-on nexedi/slapos!343

stack/erp5/buildout.cfg

@@ -551,6 +551,12 @@ eggs = ${neoppod:eggs}
 # Used by ERP5 Jupyter backend
   ipykernel
 
+# Used by DiffTool
+  xmltodict
+  deepdiff
+  unidiff
+  jsonpickle
+
 # parameterizing the version of the generated python interpreter name by the
 # python section version causes dependency between this egg section and the
 # installation of python, which we don't want on an instance
@@ -768,3 +774,11 @@ sympy = 1.1.1
 # Required by:
 # openpyxl==2.4.8
 jdcal = 1.3
+
+xmltodict = 0.11.0
+deepdiff = 3.3.0
+unidiff = 0.5.5
+
+# Required by:
+# deepdiff = 3.3.0
+jsonpickle = 0.9.6