cache date formatter for creating only once. For performance improvem…

[rahimkhalid]

…ent.

Checklist

• [ ] New Extension
• [ ] New Test
• [ ] Changed more than one extension, but all changes are related
• [x] Trivial change (doesn't require changelog)

[EZSwiftExtensionsBot]

	1 Error
:no_entry_sign:	Making non-trivial change requires changelog entry! Please, set trivial change or add entry to changelog.

	3 Messages
:book:	Executed 204 tests, with 0 failures (0 unexpected) in 5.238 (5.459) seconds
:book:	Executed 189 tests, with 0 failures (0 unexpected) in 4.402 (4.596) seconds
:book:	Executed 126 tests, with 0 failures (0 unexpected) in 3.879 (4.005) seconds

Generated by :no_entry_sign: Danger