t/config: test --get-urlmatch for git <2.26

While git 1.8.5 learned --get-urlmatch, git did not learn to
match URLs against wildcards until 2.26.  So only depend on
1.8.5 for this test since 2.26 is too new.

Reported-by: Ali Alnubani <alialnu@nvidia.com>
Link: https://public-inbox.org/meta/DM6PR12MB49106F8E3BD697B63B943A22DADB0@DM6PR12MB4910.namprd12.prod.outlook.com/
Tested-by: Ali Alnubani <alialnu@nvidia.com>
(cherry picked from commit 382a2bdd54cfb6c28a935c2b9fe4f1b1c2f469c4)