SSL: add DigiCert Global Root G2 to the list of root certificates (#7414)

Author: oioki

src/docs/product/security/ssl.mdx

@@ -87,6 +87,12 @@ Valid until: 10/Nov/2031
 Serial Number: 08:3B:E0:56:90:42:46:B1:A1:75:6A:C9:59:91:C7:4A
 SHA1 Fingerprint: A8:98:5D:3A:65:E5:E5:C4:B2:D7:D6:6D:40:C6:DD:2F:B1:9C:54:36
 SHA256 Fingerprint: 43:48:A0:E9:44:4C:78:CB:26:5E:05:8D:5E:89:44:B4:D8:4F:96:62:BD:26:DB:25:7F:89:34:A4:43:C7:01:61
+
+DigiCert Global Root G2
+Valid until: 15/Jan/2038
+Serial Number: 03:3A:F1:E6:A7:11:A9:A0:BB:28:64:B1:1D:09:FA:E5
+SHA1 Fingerprint: DF:3C:24:F9:BF:D6:66:76:1B:26:80:73:FE:06:D1:CC:8D:4F:82:A4
+SHA256 Fingerprint: CB:3C:CB:B7:60:31:E5:E0:13:8F:8D:D3:9A:23:F9:DE:47:FF:C3:5E:43:C1:14:4C:EA:27:D4:6A:5A:B1:CB:5F
 ```
 
 - [Let's Encrypt](https://letsencrypt.org/certificates/)