build: update actions/setup-java action to v4 (googleapis#2015)

* deps: update actions/setup-java action to v4

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

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Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

.github/workflows/conformance.yaml

@@ -29,7 +29,7 @@ jobs:
         repository: googleapis/cloud-bigtable-clients-test
         ref: main
         path: cloud-bigtable-clients-test
-    - uses: actions/setup-java@v3
+    - uses: actions/setup-java@v4
       with:
         distribution: zulu
         java-version: 8