fix: [torrust#132] deprecate chrono function warning

```
warning: use of deprecated associated function `chrono::NaiveDateTime::from_timestamp`: use `from_timestamp_opt()` instead
  --> src/upgrades/from_v1_0_0_to_v2_0_0/databases/sqlite_v2_0_0.rs:53:41
   |
53 |     let naive_datetime = NaiveDateTime::from_timestamp(timestamp, 0);
   |                                         ^^^^^^^^^^^^^^
   |
   = note: `#[warn(deprecated)]` on by default
```

src/upgrades/from_v1_0_0_to_v2_0_0/databases/sqlite_v2_0_0.rs

@@ -46,11 +46,12 @@ impl TorrentRecordV2 {
     }
 }
 
+#[must_use]
 pub fn convert_timestamp_to_datetime(timestamp: i64) -> String {
     // The expected format in database is: 2022-11-04 09:53:57
     // MySQL uses a DATETIME column and SQLite uses a TEXT column.
 
-    let naive_datetime = NaiveDateTime::from_timestamp(timestamp, 0);
+    let naive_datetime = NaiveDateTime::from_timestamp_opt(timestamp, 0).expect("Overflow of i64 seconds, very future!");
     let datetime_again: DateTime<Utc> = DateTime::from_utc(naive_datetime, Utc);
 
     // Format without timezone