arrow

MINOR: [Docs] Update URL to Go libraries in README.md (#44354)

### Rationale for this change
Adapt the documentation to the new url to reflect the change made in #44293 (moving the Go libraries to a separate repository)

### What changes are included in this PR?
I updated the url to the Go libraries in the README.md file

### Are these changes tested?
N/A

### Are there any user-facing changes?
N/A

Authored-by: GeniusTimo <mail@geniustimo.de>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>