chore: update checkpoint template labels (#4810)

.github/CHECKPOINT_ISSUE_TEMPLATE.md

@@ -1,6 +1,6 @@
 ---
 title: "cron: update known_blocks.yaml"
-labels: ["Enhancement", "Priority: 3 - Medium"]
+labels: ["Type: Task"]
 ---
 
 Forest uses checkpoints to improve performance when loading a snapshot. Without checkpoints, the blockchain has to be fully traversed to verify we have the right genesis block. Checkpoints short-circuit this search and shave off tens of minutes in boot time.