migrate to openapi 3.1.0

templates/openapi.yaml

@@ -1,20 +1,38 @@
-openapi: 3.0.0
+openapi: 3.1.0
 
 info:
-  title: T-REX, the DormCon REX API
-  description: Backend for REX events
+  title: T-REX
+  summary: The DormCon REX API!
+  description:
+    This API hosts the structured data and information for the [REX Events
+    page](https://dormcon.mit.edu/rex/events). Feel free to use it for your own
+    purposes! The structure of the JSON is documented as `TRexAPIResponse` in
+    [types.ts](https://github.com/mit-dormcon/website/blob/main/components/t-rex/types.ts)
+    in the main DormCon website repository.
   version: 1.0.0
+  contact:
+    name: DormCon Tech Chair
+    email: dormcon-tech-chair@mit.edu
+
+tags:
+  - name: Raw Data
+    description: Returns raw REX data without filtering or narrowing.
+    x-displayName: Raw Data
 
 servers:
   - url: https://rex.mit.edu
 
+jsonSchemaDialect: https://spec.openapis.org/oas/3.1/dialect/base
+
 paths:
   /api.json:
     get:
-      summary: Returns all REX Event data.
+      summary: All REX Event data
+      tags:
+        - Raw Data
       responses:
         "200":
-          description: A JSON object containing all REX Event data.
+          description: This returns a JSON object containing all REX Event data.
           content:
             application/json:
               schema:
@@ -73,8 +91,9 @@ components:
           items:
             type: string
         group:
-          type: string
-          nullable: true
+          type:
+            - "string"
+            - "null"
         emoji:
           type: array
           items: