Update Academic Course query.

The credential was refactored some time ago to remove the inline
context. This updates the query to match those earlier changes.

Author: BigBlueHat

credentials/academic-course-credential/queries.json

@@ -6,11 +6,8 @@
       "example": {
         "@context": [
           "https://www.w3.org/2018/credentials/v1",
-          "https://w3id.org/security/suites/ed25519-2020/v1",
           "https://purl.imsglobal.org/spec/ob/v3p0/context-3.0.2.json",
-          {
-            "tln": "https://tln.asu.edu/terms/"
-          }
+          "https://examples.vcplayground.org/contexts/academic-course-credential/v1.json"
         ],
         "type": ["OpenBadgeCredential"]
       },