Update core 8.3.0

web/vendor/zendframework/zend-feed/doc/book/consuming-atom.md

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+# Consuming Atom Feeds
+
+`Zend\Feed\Reader\Feed\Atom` is used in much the same way as
+`Zend\Feed\Reader\Feed\Rss`. It provides the same access to feed-level
+properties and iteration over entries in the feed. The main difference is in the
+structure of the Atom protocol itself. Atom is a successor to RSS; it is a
+more generalized protocol and it is designed to deal more easily with feeds that
+provide their full content inside the feed, splitting RSS' `description` tag
+into two elements, `summary` and `content`, for that purpose.
+
+## Basic Use of an Atom Feed
+
+Read an Atom feed and print the `title` and `summary` of each entry:
+
+```php
+$feed = Zend\Feed\Reader\Reader::import('http://atom.example.com/feed/');
+echo 'The feed contains ' . $feed->count() . ' entries.' . "\n\n";
+foreach ($feed as $entry) {
+    echo 'Title: ' . $entry->getTitle() . "\n";
+    echo 'Description: ' . $entry->getDescription() . "\n";
+    echo 'URL: ' . $entry->getLink() . "\n\n";
+}
+```
+
+> ## Importing requires an HTTP client
+>
+> To import a feed, you will need to have an [HTTP client](zend.feed.http-clients)
+> available. 
+>
+> If you are not using zend-http, you will need to inject `Reader` with the HTTP
+> client. See the [section on providing a client to Reader](http-clients.md#providing-a-client-to-reader).
+
+In an Atom feed, you can expect to find the following feed properties:
+
+- `title`: The feed's title, same as RSS' channel title.
+- `id`: Every feed and entry in Atom has a unique identifier.
+- `link`: Feeds can have multiple links, which are distinguished by a `type`
+  attribute. The equivalent to RSS's channel link would be `type="text/html"`.
+  If the link is to an alternate version of the same content that's in the feed,
+  it would have a `rel="alternate"` attribute.
+- `subtitle`: The feed's description, equivalent to RSS' channel description.
+- `author`: The feed's author, with `name` and `email` sub-tags.
+
+Atom entries commonly have the following properties:
+
+- `id`: The entry's unique identifier.
+- `title`: The entry's title, same as RSS item titles.
+- `link`: A link to another format or an alternate view of this entry.
+   The link property of an atom entry typically has an `href` attribute.
+- `summary`: A summary of this entry's content.
+- `content`: The full content of the entry; can be skipped if the feed just
+   contains summaries.
+- `author`: with `name` and `email` sub-tags like feeds have.
+- `published`: the date the entry was published, in RFC 3339 format.
+- `updated`: the date the entry was last updated, in RFC 3339 format.
+
+Where relevant, `Zend\Feed` supports a number of common RSS extensions including
+Dublin Core; Content, Slash, Syndication, and Syndication/Thread; and several
+others in common use on blogs.
+
+For more information on Atom and plenty of resources, see
+[http://www.atomenabled.org/](http://www.atomenabled.org/).