+00:00 timezone bug

[rahulpratik]

Describe the bug

When we have +00:00 timezone offset like 'Europe/London" dayjs gets users timezone offset, which causes incorrect time showing in different cases.

Example

Current behavior:
dayjs('2021-10-31T15:00:00+00:00').tz('Europe/London').format() // 2021-10-31T15:00:00Z

Expected behavior
Behavior after fix:
dayjs('2021-10-31T15:00:00+00:00').tz('Europe/London').format() // 2021-10-31T15:00:00+00:00

Information

• Day.js Version [v1.11.20]
• OS: [iOS]
• Browser [Chrome 147]
• Time zone: [BST]