fix bul json si ects None

app/scodoc/sco_bulletins_json.py

@@ -189,10 +189,10 @@ def formsemestre_bulletinetud_published_dict(
     d["ue_capitalisee"] = []
     for ue in ues:
         ue_status = nt.get_etud_ue_status(etudid, ue["ue_id"])
-        try:
-            ects_txt = str(int(ue["ects"]))
-        except ValueError:
+        if ue["ects"] is None:
             ects_txt = ""
+        else:
+            ects_txt = f"{ue['ects']:2.3g}"
         u = dict(
             id=ue["ue_id"],
             numero=scu.quote_xml_attr(ue["numero"]),