Modify server secrets example to include git service key variables

serversecrets.example

@@ -25,6 +25,7 @@ vpn_server_pubkey: ***
 
 # VPN Client Private Keys
 mail_service_privkey: *** 
+git_service_privkey: ***
 invidious_service_privkey: *** 
 searxng_service_privkey: *** 
 nextcloud_service_privkey: *** 
@@ -34,6 +35,7 @@ user_privkey: ***
 
 # VPN Client Public Keys
 mail_service_pubkey: *** 
+git_service_pubkey: ***
 invidious_service_pubkey: ***
 searxng_service_pubkey: ***
 nextcloud_service_pubkey: ***