[mobile-broadband-provider-info] us: added MCCMNC 310280 to AT&T

[Lubomir Rintel <lkundrak src gnome org>]

commit fe2e23b50939bb3f2d78ce356ed10ae69865a9d8
Author: huntekye <unsepttrium173 gmail com>
Date:   Wed Feb 2 20:05:34 2022 +0000

    us: added MCCMNC 310280 to AT&T
    
    "Received error in log "Could not find settings: Operator ID '310280' not
    found in service provider database". I use AT&T in the US, so I've added
    that ID."
    
    https://gitlab.gnome.org/GNOME/mobile-broadband-provider-info/-/merge_requests/58

 serviceproviders.xml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/serviceproviders.xml b/serviceproviders.xml
index 890a193..1fc5bfc 100644
--- a/serviceproviders.xml
+++ b/serviceproviders.xml
@@ -13319,6 +13319,7 @@ conceived.
                        <network-id mcc="310" mnc="038"/>
                        <network-id mcc="310" mnc="090"/>
                        <network-id mcc="310" mnc="150"/>
+                       <network-id mcc="310" mnc="280"/>
                        <network-id mcc="310" mnc="410"/>
                        <network-id mcc="310" mnc="560"/>
                        <network-id mcc="310" mnc="680"/>