chore(main): release 0.39.4

[release-please[bot]]

:robot: I have created a release beep boop

0.39.4 (2023-11-08)

Bug Fixes

• gencli: Title case dot delimited segments (#1442) (a1d372c)

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[release-please[bot]]

:robot: Release is at https://github.com/googleapis/gapic-generator-go/releases/tag/v0.39.4 :sunflower: