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

    Error: ../../../go/pkg/mod/golang.org/x/[email protected]/unix/syscall.go:83:16: undefined: unsafe.Slice
    Error: ../../../go/pkg/mod/golang.org/x/[email protected]/unix/syscall_linux.go:2256:9: undefined: unsafe.Slice
    Error: ../../../go/pkg/mod/golang.org/x/[email protected]/unix/syscall_unix.go:118:7: undefined: unsafe.Slice
    Error: ../../../go/pkg/mod/golang.org/x/[email protected]/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).

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Now that we require `go` `1.17`, this note is no longer relevant.

Test against the "oldest" supported version and the current version
of go. Go 1.17 is kept in this matrix as it is the minimum version
specified in go.mod, and maintaining compatibility with go 1.17 is
currently not much of a burden. Most projects using this module are
using newer versions than that, so we can drop the old version if
it becomes too much of a burden.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Linting is disabled on Windows, as the current build-tags do not
properly exclude non-unix platforms;

    level=info msg="[runner/filename_unadjuster] Pre-built 0 adjustments in 1.0348ms"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:28:18: Stat_t not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:29:17: Fstat not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:32:17: Fstat not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:43:13: Stat_t not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:44:17: Fstat not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:56:13: Stat_t not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:57:17: Fstat not declared by package unix"
    Error: level=error msg="[linters_context] typechecking error: D:\\a\\netns\\netns\\netns.go:71:17: Close not declared by package unix"

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Signed-off-by: yanggang <[email protected]>