tests/example: use .example TLD to prevent lookups

Tests were using mywebsite.me, which is an existing domain for which
HTTP requests timeout, this make the test slow and it is generally not OK
that the test use a real web site. Using .example, as recommended by rfc2606
prevent these problems.
19 jobs for fix/dns-example in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:24:46

passed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:34:27

passed SlapOS.Theia.ResilienceTest-ForTestRunner1-Gitlab

18:30:18

failed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:18:06

passed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:17:42

passed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:16:19

passed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:26:53

passed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:15:42

failed SlapOS.Eggs.UnitTest-TestRunner1.Python2

00:14:58

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:15:23

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:16:09

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:15:39

passed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:22:09

passed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:19:36

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:20:03

passed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:15:59

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

00:35:02

failed SlapOS.Eggs.UnitTest-TestRunner1.Python3

passed SlapOS.Theia.ResilienceTest-ForTestRunner1-Gitlab

12:29:19