DOC: 51d: updated 51Degrees repo URL for v3.2.10

The v3.2.10 branch has been migrated from the legacy git.51Degrees.com
repo to github.com.  The files on the frozen branch are exactly the same.

(cherry picked from commit 9b9e23928e22c34f758e7cd1549a3913f6f020ea)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed