Update certificates to expire in 2029

Update certificates that expire on 2021, to prolong their validity,
to make tests pass three years ahead.
diff --git a/tests/data_files/server2-sha256.crt b/tests/data_files/server2-sha256.crt
index 006d9db..f13fe64 100644
--- a/tests/data_files/server2-sha256.crt
+++ b/tests/data_files/server2-sha256.crt
@@ -1,7 +1,7 @@
 -----BEGIN CERTIFICATE-----
 MIIDfTCCAmWgAwIBAgIBBDANBgkqhkiG9w0BAQsFADA7MQswCQYDVQQGEwJOTDER
 MA8GA1UECgwIUG9sYXJTU0wxGTAXBgNVBAMMEFBvbGFyU1NMIFRlc3QgQ0EwHhcN
-MTcwNTA5MTM1MTA1WhcNMjcwNTEwMTM1MTA1WjA0MQswCQYDVQQGEwJOTDERMA8G
+MTkwMzEyMTAwNzA0WhcNMjkwMzEyMTAwNzA0WjA0MQswCQYDVQQGEwJOTDERMA8G
 A1UECgwIUG9sYXJTU0wxEjAQBgNVBAMMCWxvY2FsaG9zdDCCASIwDQYJKoZIhvcN
 AQEBBQADggEPADCCAQoCggEBAMFNo93nzR3RBNdJcriZrA545Do8Ss86ExbQWuTN
 owCIp+4ea5anUrSQ7y1yej4kmvy2NKwk9XfgJmSMnLAofaHa6ozmyRyWvP7BBFKz
@@ -11,11 +11,11 @@
 HT4P6DSYW8tzS1KW2BGiLICIaTla0w+w3lkvEcf36hIBMJcCAwEAAaOBkjCBjzAd
 BgNVHQ4EFgQUpQXoZLjc32APUBJNYKhkr02LQ5MwYwYDVR0jBFwwWoAUtFrkpbPe
 0lL2udWmlQ/rPrzH/f+hP6Q9MDsxCzAJBgNVBAYTAk5MMREwDwYDVQQKDAhQb2xh
-clNTTDEZMBcGA1UEAwwQUG9sYXJTU0wgVGVzdCBDQYIBADAJBgNVHRMEAjAAMA0G
-CSqGSIb3DQEBCwUAA4IBAQAQf85QSjAeP+l6hirPorUL+k/3BznAh/6RXdveBO3K
-uwtqK5qI59+3N+ZLXP7fr2Z5eO8qpchRgNNwT0LKglAEXGWn30PYI1GKSiqAaK0X
-CUNIrxV3qKqOLbtqP1dMdiwsmiHYrN8E9UdysObedE2yDNLpTMHPJBZ+k6FowTyZ
-IpUuabkxMBFxmLv+nOBDOiaCzintEcdJdY4F6p5j8jwMvVNVAXNfxAEwa0MoVRTt
-/GORvq4ZEfsatVA+HRi602m+dZETTWKSODrj8AuQcG8/i1AOhk3C1WNOFKj/ZSfB
-2P6EQmhLeRp4bO+3rG73T3R2yn0PZYQ7ZrjFPPKqgu+n
+clNTTDEZMBcGA1UEAwwQUG9sYXJTU0wgVGVzdCBDQYIBAzAJBgNVHRMEAjAAMA0G
+CSqGSIb3DQEBCwUAA4IBAQCI8yvc3JSUnfBoWZbyia9BZJ3ZhqbH8V4fN7Co7l5J
+5985ZRPZ6Wz8pF3Cf97VrbqTHmC8PCYwXaxUbQif4apfEhvJP0luOGefAY5S87bw
+iQHEW7WcQwVwGxRIMLqlFwhJrNDyvvilTgLeILZIsY81HY+mw1FNtzZY94SRsyth
+x2dH/bJt/GeJq6XYAwQlurU6dFFTGPsvkg9tjMJyOcYRkT6+KvlpR8xSC/V673hH
+T7o2ePkWW73wWG1Qit3de6e2eMIHNZZTSVerd/IKiPfW6ro/123EWSZXbQ3DHHLD
+/0JVgqo90NrhRJQA249h/Og43ewiex75ToVoLWuijFx/
 -----END CERTIFICATE-----