feat: Allow updating createdAt field for announcements

src/main/kotlin/app/revanced/api/configuration/APISchema.kt

@@ -63,6 +63,7 @@ class ApiAnnouncement(
     val attachments: List<String> = emptyList(),
     // Using a list instead of a set because set semantics are unnecessary here.
     val tags: List<String> = emptyList(),
+    val createdAt: LocalDateTime,
     val archivedAt: LocalDateTime? = null,
     val level: Int = 0,
 )

src/main/kotlin/app/revanced/api/configuration/repository/AnnouncementRepository.kt

@@ -120,6 +120,7 @@ internal class AnnouncementRepository(private val database: Database) {
             it.author = new.author
             it.title = new.title
             it.content = new.content
+            it.createdAt = new.createdAt
             it.archivedAt = new.archivedAt
             it.level = new.level