Fix failed to parse date for timezone format

[jeankhawand]

Fix Background

on my local instance I get a bunch of error logs:

[ERROR] rss: date parser: failed to parse date "Sat, 18 Mar 2023 20:21:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Sat, 19 Aug 2023 20:20:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Tue, 31 Jan 2023 20:20:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Fri, 31 Mar 2023 20:19:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Tue, 28 Mar 2023 20:19:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Thu, 9 Feb 2023 20:19:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Mon, 24 Jul 2023 20:18:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Mon, 2 Oct 2023 20:17:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Thu, 5 Oct 2023 20:16:00 America/Los_Angeles" (entry GUID = {{ }  })
[ERROR] rss: date parser: failed to parse date "Sat, 19 Aug 2023 20:16:00 America/Los_Angeles" (entry GUID = {{ }  })

fix(date-parser): failed to parse date "Fri, 31 Mar 2023 20:19:00 America/Los_Angeles" by adding timezone to invalidTimezoneReplacer
test(date-parser): add TestParseRSSDateTimezone unit test

Do you follow the guidelines?

• I have tested my changes
• I read this document: https://miniflux.app/faq.html#pull-request