erp5: Add eggs for strict json schema validation

See merge request nexedi/slapos!1118

stack/erp5/buildout.cfg

@@ -557,6 +557,10 @@ eggs = ${neoppod:eggs}
 # OpenId Connect
   oic
 
+# json schema validation
+  strict-rfc3339
+  jsonschema[format]
+
 # 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
@@ -764,3 +768,8 @@ pyjwkest = 1.4.2
 alabaster = 0.7.12
 future = 0.18.2
 pycryptodomex = 3.10.1
+
+strict-rfc3339 = 0.7
+webcolors = 1.10
+rfc3987 = 1.3.8
+jsonpointer = 2.2