srpm/go.lua meta: Set `%gourl` after `forge.meta` call
`forge.meta` sanitizes the result of `%forgeurl`, so we want to set
`%gourl` based on the sanitzed value. For example, `forge.meta` changes
`https://github.com/cli/cli/v2` to `https://github.com/cli/cli`.
Signed-off-by: Maxwell G <gotmax@e.email>