go.mod: upgrade golang.org/x/sys and golang.org/x/net

[mischief]

this fixes the build for openbsd/riscv64 hosts.

fixes

../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/sockcmsg_unix.go:34:9: undefined: Cmsghdr
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/syscall_openbsd.go:31:9: undefined: RawSockaddrDatalink
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/syscall_unix.go:186:38: undefined: _Socklen
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/syscall_unix.go:193:7: undefined: RawSockaddrInet4
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/syscall_unix.go:201:9: undefined: RawSockaddrInet6
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/syscall_unix.go:207:7: undefined: RawSockaddrUnix
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/fcntl.go:14:30: undefined: SYS_FCNTL
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/fcntl.go:31:42: undefined: Flock_t
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/fdset.go:11:12: undefined: FdSet
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/fdset.go:16:12: undefined: FdSet
../../go/pkg/mod/golang.org/x/sys@v0.0.0-20210514084401-e8d321eab015/unix/fdset.go:16:12: too many errors

and

../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/cmsghdr.go:10:10: undefined: cmsghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/cmsghdr.go:11:10: undefined: cmsghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/cmsghdr.go:12:10: undefined: cmsghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/cmsghdr_bsd.go:10:10: undefined: cmsghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/iovec_64bit.go:13:10: undefined: iovec
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:12:10: undefined: msghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:12:28: undefined: iovec
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:27:10: undefined: msghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:34:10: undefined: msghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:38:10: undefined: msghdr
../../go/pkg/mod/golang.org/x/net@v0.0.0-20210405180319-a5a99cb37ef4/internal/socket/msghdr_bsd.go:38:10: too many errors

note that this also bumps minimum go version to 1.25. it would be great if this could get tagged as well so that this can be bumped in openbsd ports.