go.mod: pin golang-lru/v2 to main for expirable.Close

v2.0.7 is the last tag; the TTL sweeper got Close only on main.

(cherry picked from commit 5f39a68b39, adapted: release branch go.mod and vendor hash)

flakehashes.json

@@ -1,6 +1,6 @@
 {
   "vendor": {
-    "goModSum": "sha256-ZCJe3Dxz3jYjyz1hAb7QLMQJhrQLY78H2d+OaBpODbc=",
-    "sri": "sha256-Xzc8AYe5sJ+05IS9je/a8HjOqx1sXnIhewSCYqbQBQ4="
+    "goModSum": "sha256-CJZA52vVAb8a3rtk8P5SzsCJ9pl5I7FjOHu0AyCg+0E=",
+    "sri": "sha256-ADl65VpgS3uKYX0dYkRPPKcOelD9sJdwlq+CA0eA7Nk="
   }
 }