Set updated at timestamp for videos

Since the metadata only provides a date, set the time part to 12:00:00
(UTC).

Also fix up the deprecation warning for the creation of the initial zero
last build timestamp.

src/backends/youtube.rs

@@ -6,7 +6,7 @@ use std::path::{Path, PathBuf};
 
 use async_trait::async_trait;
 use cached::proc_macro::cached;
-use chrono::Utc;
+use chrono::{DateTime, Utc};
 use reqwest::Url;
 use rocket::futures::StreamExt;
 use ytextract::playlist::video::{Error as YouTubeVideoError, Video as YouTubePlaylistVideo};
@@ -197,6 +197,11 @@ impl From<YouTubeVideoWithStream> for Item {
             .iter()
             .max_by_key(|tn| tn.width * tn.height)
             .map(|tn| tn.url.clone());
+        let timestamp = video
+            .date()
+            .and_hms_opt(12, 0, 0)
+            .expect("Invalid hour, minute and/or second");
+        let updated_at = DateTime::from_utc(timestamp, Utc);
 
         Item {
             title: video.title().to_string(),
@@ -208,7 +213,7 @@ impl From<YouTubeVideoWithStream> for Item {
             guid: id,
             keywords: Default::default(),
             image,
-            updated_at: Utc::now(), // TODO: Get a decent timestamp somewhere?!
+            updated_at,
         }
     }
 }

src/feed.rs

@@ -28,7 +28,9 @@ pub(crate) fn construct(backend_id: &str, config: &Config, channel: Channel) ->
                 .unwrap_or_default(),
         )
         .build();
-    let mut last_build = DateTime::<Utc>::from_utc(NaiveDateTime::from_timestamp(0, 0), Utc);
+    let unix_timestamp = NaiveDateTime::from_timestamp_opt(0, 0)
+        .expect("Out-of-range seconds or invalid nanoseconds");
+    let mut last_build = DateTime::from_utc(unix_timestamp, Utc);
     let generator = String::from(concat!(
         env!("CARGO_PKG_NAME"),
         " ",