Update fields in schema.

Author: nikoshell

src/content/config.ts

@@ -109,10 +109,10 @@ const speakers = defineCollection({
     submissions: z.array(reference("sessions")),
     affiliation: z.string().nullable(),
     homepage: z.string().nullable(),
-    gitx_url: z.string().url().nullable(),
+    gitx_url: z.string().url().nullable().optional(),
     linkedin_url: z.string().url().nullable(),
     mastodon_url: z.string().url().nullable(),
-    bluesky_url: z.string().url().nullable(),
+    bluesky_url: z.string().url().nullable().optional(),
     twitter_url: z.string().url().nullable(),
   }),
 });