chore(deps): update cimg/openjdk docker tag to v21.0.8 (#783)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| cimg/openjdk | docker | patch | `21.0.6` -> `21.0.8` |

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.circleci/config.yml

@@ -6,7 +6,7 @@ orbs:
 executors:
   jdk:
     docker:
-      - image: cimg/openjdk:21.0.6
+      - image: cimg/openjdk:21.0.8
   node:
     docker:
       - image: cimg/node:22.15.0