Update go-server deps

[wing328]

to close #24058

PR checklist

• Read the contribution guidelines.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

---

Summary by cubic

Raise Go server template, samples, CI, and tests to Go 1.25 and github.com/go-chi/chi/v5 v5.2.4. Previously these used Go 1.18 and chi v5.2.2; generated servers now target Go 1.25 and chi v5.2.4.

• Changes

  • Template go.mod.mustache: go 1.18 → 1.25; github.com/go-chi/chi/v5 v5.2.2 → v5.2.4.
  • Sample go.mod: set go 1.25; chi-based samples pin github.com/go-chi/chi/v5 v5.2.4.
  • CI samples workflow uses Go 1.25.
  • Sample test updated to expect go 1.25.

• Migration

  • Build and test with Go 1.25+.
  • Regenerate Go servers and run go mod tidy.

^{Written for commit 4a8e500. Summary will update on new commits.}

cc @antihax (2017/11) @grokify (2018/07) @kemokemo (2018/09) @jirikuncar (2021/01) @ph4r5h4d (2021/04) @lwj5 (2023/04)

[cubic-dev-ai]

No issues found across 9 files

_{Re-trigger cubic}