Atom published and updated datetime formats not being parsed properly

To be added to area-System.ServiceModel

Valid Atom date formats for updated and published times are not being parsed properly.

Only some of the valid Atom date constructs parse properly to DateTimeOffset. The last two in the list below do not parse properly which include the time zone offset. Only zulu time formats seem to parse.

Example Date constructs:

2003-12-13T18:30:02Z
2003-12-13T18:30:02.25Z
**2003-12-13T18:30:02+01:00
2003-12-13T18:30:02.25+01:00**

Reference
[https://learn.microsoft.com/en-us/dotnet/api/system.servicemodel.syndication.syndicationitem.lastupdatedtime?view=dotnet-plat-ext-8.0](url)

The Atom feed processing should be modified to support all valid datetime formats.

Referenced list of feeds for testing [https://www.canada.ca/en/news/web-feeds.html ](url)

Inizia da System.ServiceModel.Syndication.SyndicationItem.LastUpdatedTime e dal riferimento API collegato, quindi riproduci il parsing dei quattro esempi Atom updated, in particolare degli offset +01:00. Il lavoro è completato quando i formati datetime Atom validi con offset di fuso orario vengono analizzati correttamente, inclusi i secondi frazionari; l’issue non indica alcun file sorgente né alcun test da eseguire.

Scritto dal modello di indicizzazione a partire dal testo della issue.