Updated template gitignore with fastlane best practices (#33186)
Updated template gitignore with fastlane best practices (#33186)

Summary:
See https://docs.fastlane.tools/best-practices/source-control/

This commit reflects the best practices as outlined by fastlane.

## Changelog

[iOS] [Fixed] - Improved template fastlane gitignore

Pull Request resolved: https://github.com/facebook/react-native/pull/33186

Test Plan: no test plan

Reviewed By: cortinico

Differential Revision: D34518831

Pulled By: motiz88

fbshipit-source-id: eee1d332f24caa37bc48fd058bf0eb0e73f6bc1b

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