build: add fmt, lint, vulncheck to improve code readability and security

[zhoukuncheng]

Thanks to the gpodder2go project, it is compatible with the AntennaPod and gPodder clients very well. However, I found that the project lacked some code check tools, so I added some check targets to the Makefile and fixed issues scanned by these tools.

The main changes include:

1. Formatting and Linting: Applied gofumpt, goimports, and golangci-lint to ensure consistent code formatting and adherence to best practices.

2. Vulnerability Scanning: Ran govulncheck to identify and address potential vulnerabilities in the project dependencies.

3. Dependency Updates: Updated the go.mod and go.sum files to include the latest versions of project dependencies, addressing vulnerabilities scanned by govulncheck.

[oxtyped]

Thanks for this and the clear PR description! 🙇

I don't have any issues with PR and the tools used in general.

Just have one quick question, I noticed that the linter (probably) is removing the explicit returns. I usually purposefully write a return for readability purposes, so this is something quite curious for me. Do you know what might be the rationale behind this removal?

[zhoukuncheng]

I added the golangci-lint command inspired by the miniflux's Makefile.

Upon running the linter, I received the following warning:

pkg/apis/handlers.go:154:2: S1023: redundant return statement (gosimple)
return
^

The documentation for the S1023 rule recommends removing redundant return:

S1023 - Omit redundant control flow
Functions that have no return value do not need a return statement as the final statement of the function.

[oxtyped]

Thanks for the reference!

dominikh/go-tools#35

lgtm