build: update image(s) version

- bun: (canary) v1.2.21-canary.20250825.1, (latest) v1.2.21
- nodejs:
current: v23.11.0
jod: v22.15.0
iron: v20.19.1
hydrogen: v18.20.8
- distro: alpine,debian-slim,debian

Author: github-actions[bot]

versions.json

@@ -1,7 +1,7 @@
 {
   "bun": {
-    "latest": "v1.2.20",
-    "canary": "v1.2.20-canary.20250824.1"
+    "latest": "v1.2.21",
+    "canary": "v1.2.21-canary.20250825.1"
   },
   "nodejs": {
     "23": {