erp5_payroll_l10n_fr: fix Cannot decode using encoding "ascii" warning

17 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

00:58:39

passed ERP5.PerformanceTest-Master

00:32:22

failed ERP5.UnitTest-Master

02:13:30

passed SlapOS.Eggs.UnitTest-Master.Python2

00:18:10

passed SlapOS.Eggs.UnitTest-Master.Python3

00:26:00

passed ERP5.UnitTest-Master

01:36:16

passed SlapOS.Eggs.UnitTest-Master.Python2

passed SlapOS.Eggs.UnitTest-Master.Python2

00:24:11

passed SlapOS.Eggs.UnitTest-Master.Python2

00:21:24

passed SlapOS.Eggs.UnitTest-Master.Python3

passed SlapOS.Eggs.UnitTest-Master.Python3

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:20

passed SlapOS.Eggs.UnitTest-Master.Python3

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:45

passed SlapOS.Eggs.UnitTest-Master.Python3

00:19:23

passed SlapOS.Eggs.UnitTest-Master.Python3

00:20:46

passed SlapOS.Eggs.UnitTest-Master.Python3