`go fix`: run and add to CI

[TyHil]

GoLang 1.26 introduces the go fix command which modernizes parts of the language. For this issue do 3 things:

1. Update to GoLang 1.26. Don't forget to change the version in the Dockerfile file.
2. Run the go fix command on the codebase.
3. Create a new GitHub action similar to .github/workflows/go.yml that runs go fix with the diff flag and fails if there are any changes. Don't add this to the existing .github/workflows/go.yml workflow as there is no need to run this on both Ubuntu and Windows.

Related to #401 and UTDNebula/api-tools#178

[justinschwerdtfeger]

While we're thinking about this, I found a tool called gofumpt. It adds more opinionated formatting rules to gofmt, making code format more consistent. Would this be a good idea to add as well?

[TyHil]

Sounds nice, and it's backwards compatible so easy to remove if needed. New issue for it?