Add last update time to Updates Tab (closes #5466)

Co-authored-by: datreesezcup <datreesezcup@users.noreply.github.com>

app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt

@@ -68,6 +68,7 @@ import logcat.LogPriority
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 import java.io.File
+import java.util.Date
 import java.util.concurrent.CopyOnWriteArrayList
 import java.util.concurrent.atomic.AtomicBoolean
 import java.util.concurrent.atomic.AtomicInteger
@@ -225,6 +226,11 @@ class LibraryUpdateService(
         updateJob?.cancel()
         ioScope?.cancel()
 
+        // If this is a chapter update; set the last update time to now
+        if (target == Target.CHAPTERS) {
+            preferences.libraryUpdateLastTimestamp().set(Date().time)
+        }
+
         // Update favorite manga
         val categoryId = intent.getLongExtra(KEY_CATEGORY, -1L)
         addMangaToQueue(categoryId)