Make cfp date and link optional (#524)

* make cfp deadline and link optional

.github/ISSUE_TEMPLATE/add_conference.yml

@@ -53,15 +53,15 @@ body:
       description: Provide the URL for the Call for Proposals (CFP) (make sure to include `https://`).
       placeholder: "https://example.com/cfp"
     validations:
-      required: true
+      required: false
   - type: input
     id: cfp_deadline
     attributes:
       label: CFP Deadline
       description: Enter the deadline for submitting CFPs (YYYY-MM-DD).
       placeholder: "YYYY-MM-DD"
     validations:
-      required: true
+      required: false
   - type: textarea
     id: conference_description
     attributes: