go.mod: update minimum version to go1.17

[thaJeztah]

golang.org/x/sys now requires go1.17 as a minimum, and otherwise fails:

Error: ../../../go/pkg/mod/golang.org/x/sys@v0.2.0/unix/syscall.go:83:16: undefined: unsafe.Slice
Error: ../../../go/pkg/mod/golang.org/x/sys@v0.2.0/unix/syscall_linux.go:2256:9: undefined: unsafe.Slice
Error: ../../../go/pkg/mod/golang.org/x/sys@v0.2.0/unix/syscall_unix.go:118:7: undefined: unsafe.Slice
Error: ../../../go/pkg/mod/golang.org/x/sys@v0.2.0/unix/sysvshm_unix.go:33:7: undefined: unsafe.Slice

unsafe.Slice was added in go1.17; https://pkg.go.dev/unsafe#Slice

Now that go1.17 is the minimum version, we cal also replace the deprecated io/ioutil package (which was deprecated in go1.16).

[jeffwidman]

Oh interesting, I was looking at golang/sys@0981d60 when I merged #58:

Note that this does not prevent users with earlier go versions from successfully building packages from this module.

Didn't consider the fact that newer stuff would creep in.

[jeffwidman]

I looked at dropping us back to v0.1.0, but even that still uses unsafe.Slice(): https://github.com/golang/sys/blame/v0.1.0/unix/syscall_unix.go#L118

Since old versions of this lib continue to work just fine, I'm 👍 on dropping support for go < 1.17 and will make our lives a little easier going forward... rather do that than revert all the way back to a non-tagged version.

[thaJeztah]

Since old versions of this lib continue to work just fine, I'm 👍 on dropping support for go < 1.17 and will make our lives a little easier going forward... rather do that than revert all the way back to a non-tagged version.

Yes, I agree. Dropping < 1.17 seems very reasonable to me. I'm happy to see more activity again on this project (although the lack of activity but it being used by various important projects, without much issues, also shows that "lack of activity" isn't necessarily bad: perhaps it's just "mature and stable")

I think we have a "fairly good understanding" who the consumers are of this module; https://grep.app/search?q=github.com/vishvananda/netns

While that list may not be fully accurate, it's still a fairly short list. There will be many other projects getting it as indirect dependency, but I think most of the direct consumers are already requiring more current Go versions for other reasons. If there are issues with dropping < 1.17, I expect those projects to let that know. It's a small world; most of those projects are familiar with each other, and will know who to reach out to.