Use minimum build number when merging master indexes

Some master indexes are used across multiple builds. It makes sense to
use the minimum build number, much like how we use the minimum
timestamp.

Signed-off-by: Graham <gpe@openrs2.org>

archive/src/main/kotlin/org/openrs2/archive/cache/CacheImporter.kt

@@ -27,6 +27,7 @@ import java.time.OffsetDateTime
 import java.time.ZoneOffset
 import javax.inject.Inject
 import javax.inject.Singleton
+import kotlin.math.min
 
 @Singleton
 public class CacheImporter @Inject constructor(
@@ -376,8 +377,7 @@ public class CacheImporter @Inject constructor(
                     check(oldGameId == gameId)
 
                     if (oldBuild != null && build != null) {
-                        check(oldBuild == build)
-                        newBuild = oldBuild
+                        newBuild = min(oldBuild, build)
                     } else if (oldBuild != null) {
                         newBuild = oldBuild
                     } else {