Fix automatic backups not working

Apparently they die if you rename a worker class.

(cherry picked from commit d25ba23079e72d1cff05bfcd00b5f9830a086821)

# Conflicts:
#	app/build.gradle.kts

app/src/main/java/eu/kanade/tachiyomi/Migrations.kt

@@ -363,6 +363,9 @@ object Migrations {
                     }
                 }
             }
+            if (oldVersion < 100) {
+                BackupCreateJob.setupTask(context)
+            }
             return true
         }