Conver your array to slice. For example
func array2Slice(m [8][12]string) string {
slice := make(string, len(m))
for r := 0; r < len(m); r++ {
cols := make(string, len(m[r]))
for c := 0; c < len(m[r]); c++ {
cols[c] = m[r][c]
}
slice[r] = cols
}
return slice
}
To use in your code, just
slice := array2Slice(m)
w := csv.NewWriter(os.Stdout)
w.WriteAll(slice)