Update Go to 1.17

[110y]

• Update Go version for the go.mod
  • Since this project already uses 1.17 for the tests, it would be better to use 1.17 for go.mod as well.
• Fix Go container image version on the Dockerfile.
  • Basically, it would be better to fix the image version as much as possible for reproducible builds.

[110y]

After 1.17, now indirect modules are grouped by another require.

https://golang.org/doc/go1.17#go-command

For the go command to correctly resolve transitive imports using the pruned module graph, the go.mod file for each module needs to include more detail about the transitive dependencies relevant to that module. If a module specifies go 1.17 or higher in its go.mod file, its go.mod file now contains an explicit require directive for every module that provides a transitively-imported package. (In previous versions, the go.mod file typically only included explicit requirements for directly-imported packages.)

[110y]

@latenssi @nanuuki

How about this change...?

[latenssi]

@110y Thank you for the PR! This PR adds new dependencies, we are going through them one by one. This is a bit laborious and as updating the Go version is not a priority I hope you understand this PR might take a while :) I did the update on main and it produced the exact same version of the go.mod file you are presenting here, so this PR seems good to go 👍 We will be merging it in tomorrow.