go/go.mod: v↑ go 1.14 -> go 1.18

We will soon want to use generics and `any` which are available only for go >= 1.18 .

The other changes in go.sum and go.mod are there because after just

    -go 1.14
    +go 1.18

the build stopped to work and asked to do `go mod tidy`

go/go.mod

 module lab.nexedi.com/kirr/neo/go
 
-go 1.14
+go 1.18
 
 require (
 	github.com/DataDog/czlib v0.0.0-20210322182103-8087f4e14ae7
@@ -24,5 +24,6 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	golang.org/x/sys v0.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )