Bump org.spigotmc:spigot-api

Bumps org.spigotmc:spigot-api from 1.20.6-R0.1-SNAPSHOT to 1.21-R0.1-SNAPSHOT.

---
updated-dependencies:
- dependency-name: org.spigotmc:spigot-api
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle.kts

@@ -21,7 +21,7 @@ dependencies {
 
     // Other dependencies that are not required or already available at runtime
     compileOnly("org.projectlombok:lombok:1.18.32")
-    compileOnly("org.spigotmc:spigot-api:1.20.6-R0.1-SNAPSHOT")
+    compileOnly("org.spigotmc:spigot-api:1.21-R0.1-SNAPSHOT")
 
     // Enable lombok annotation processing
     annotationProcessor("org.projectlombok:lombok:1.18.32")