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 f8a5b8b..b31be6b 100644
--- a/tests/data_files/server2-sha256.crt
+++ b/tests/data_files/server2-sha256.crt
@@ -1,7 +1,7 @@
 -----BEGIN CERTIFICATE-----
 MIIDNzCCAh+gAwIBAgIBAjANBgkqhkiG9w0BAQsFADA7MQswCQYDVQQGEwJOTDER
 MA8GA1UECgwIUG9sYXJTU0wxGTAXBgNVBAMMEFBvbGFyU1NMIFRlc3QgQ0EwHhcN
-MTEwMjEyMTQ0NDA2WhcNMjEwMjEyMTQ0NDA2WjA0MQswCQYDVQQGEwJOTDERMA8G
+MTkwMjEwMTQ0NDA2WhcNMjkwMjEwMTQ0NDA2WjA0MQswCQYDVQQGEwJOTDERMA8G
 A1UECgwIUG9sYXJTU0wxEjAQBgNVBAMMCWxvY2FsaG9zdDCCASIwDQYJKoZIhvcN
 AQEBBQADggEPADCCAQoCggEBAMFNo93nzR3RBNdJcriZrA545Do8Ss86ExbQWuTN
 owCIp+4ea5anUrSQ7y1yej4kmvy2NKwk9XfgJmSMnLAofaHa6ozmyRyWvP7BBFKz
@@ -10,11 +10,11 @@
 hYvai0Re4hjGYi/HZo36Xdh98yeJKQHFkA4/J/EwyEoO79bex8cna8cFPXrEAjya
 HT4P6DSYW8tzS1KW2BGiLICIaTla0w+w3lkvEcf36hIBMJcCAwEAAaNNMEswCQYD
 VR0TBAIwADAdBgNVHQ4EFgQUpQXoZLjc32APUBJNYKhkr02LQ5MwHwYDVR0jBBgw
-FoAUtFrkpbPe0lL2udWmlQ/rPrzH/f8wDQYJKoZIhvcNAQELBQADggEBAGGEshT5
-kvnRmLVScVeUEdwIrvW7ezbGbUvJ8VxeJ79/HSjlLiGbMc4uUathwtzEdi9R/4C5
-DXBNeEPTkbB+fhG1W06iHYj/Dp8+aaG7fuDxKVKHVZSqBnmQLn73ymyclZNHii5A
-3nTS8WUaHAzxN/rajOtoM7aH1P9tULpHrl+7HOeLMpxUnwI12ZqZaLIzxbcdJVcr
-ra2F00aXCGkYVLvyvbZIq7LC+yVysej5gCeQYD7VFOEks0jhFjrS06gP0/XnWv6v
-eBoPez9d+CCjkrhseiWzXOiriIMICX48EloO/DrsMRAtvlwq7EDz4QhILz6ffndm
-e4K1cVANRPN2o9Y=
+FoAUtFrkpbPe0lL2udWmlQ/rPrzH/f8wDQYJKoZIhvcNAQELBQADggEBAC465FJh
+Pqel7zJngHIHJrqj/wVAxGAFOTF396XKATGAp+HRCqJ81Ry60CNK1jDzk8dv6M6U
+HoS7RIFiM/9rXQCbJfiPD5xMTejZp5n5UYHAmxsxDaazfA5FuBhkfokKK6jD4Eq9
+1C94xGKb6X4/VkaPF7cqoBBw/bHxawXc0UEPjqayiBpCYU/rJoVZgLqFVP7Px3sv
+a1nOrNx8rPPI1hJ+ZOg8maiPTxHZnBVLakSSLQy/sWeWyazO1RnrbxjrbgQtYKz0
+e3nwGpu1w13vfckFmUSBhHXH7AAS/HpKC4IH7G2GAk3+n8iSSN71sZzpxonQwVbo
+pMZqLmbBm/7WPLc=
 -----END CERTIFICATE-----