ci: Update go test version (#1615)

## Description

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> Should include a concise description of the changes (bug or feature),
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> impact, along with a summary of the solution

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[CONTRIBUTING.md](https://github.com/googleapis/genai-toolbox/blob/main/CONTRIBUTING.md)
- [ ] Make sure to open an issue as a

[bug/issue](https://github.com/googleapis/genai-toolbox/issues/new/choose)
before writing your code! That way we can discuss the change, evaluate
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🛠️ Fixes #<issue_number_goes_here>

.github/workflows/tests.yaml

@@ -59,7 +59,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@44694675825211faa026b3c33043df3e48a5fa00 # v6.0.0
         with:
-          go-version: "1.22"
+          go-version: "1.24"
 
       - name: Checkout code
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0