refactor: [EDXOLDMNG-218] Improves doc srtring for certificate_type e…

…mun and course_id is course_key

openedx_events/content_authoring/data.py

@@ -108,16 +108,18 @@ class CertificateConfigData:
     Attributes defined for Open edX CertificateConfig data object.
 
     Arguments:
-        certificate_type (str): certificate type.
-        course_id (str): identifier of the course to which the certificate config belongs.
+        certificate_type (str): certificate type. Possible types are certificate relevant course modes such as credit,
+        verified, professional, no-id-professional, executive-education,  paid-executive-education,
+        paid-bootcamp, masters.
+        course_key (CourseKey): identifier of the Course object.
         title (str): certificate title.
         signatories (List[CertificateSignatoryData]): contains a collection of signatures
         that belong to the certificate configuration.
         is_active (bool): indicates whether the certifivate configuration is active.
     """
 
     certificate_type = attr.ib(type=str)
-    course_id = attr.ib(type=str)
+    course_key = attr.ib(type=CourseKey)
     title = attr.ib(type=str)
     signatories = attr.ib(type=List[CertificateSignatoryData])
     is_active = attr.ib(type=bool, default=False)