fix: Updates go_url to correct location

[jsnctl]

Running a fresh make was failing for me as follows:

💤 spire-api-sdk/ make                                                                            (main)
go_url: https://storage.googleapis.com/golang/go1.23.0.linux-amd64.tar.gz
Installing go1.23.0...
curl: (22) The requested URL returned error: 403

gzip: stdin: unexpected end of file
tar: Child returned status 1
tar: Error is not recoverable: exiting now
make: *** [Makefile:106: go-check] Error 2

It appears as if the canonical location for these dependencies has recently been updated, and the https://storage.googleapis.com/golang/* repository no longer applies. See also: actions/go-versions#127

This fix updates the go_url value to the new go.dev/dl URL (as outlined in the above issues)