Update Github actions workflows from nodejs 16 to nodejs 20 before "Spring 2024"

[brackendawson]

We have deprecation warnings in our Githiub actions workflows: https://github.com/stretchr/testify/actions/runs/7971877138

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/setup-go@v4.1.0. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

[hendrywiranto]

Hello..
from the looks of it the update to node20 is on v5 of the setup-go workflow ref

should we just update it to v5? I opened a PR