Add swiftlint as a pre-commit check

[adwinross]

Currently, we run swiftlint checks on ci using cirruslabs/swiftlint-action.

The problem here is that cirruslabs/swiftlint-action does not provide an option to run checks using the swiftlint config, which is resulting in ci failure as its linting flutter ios code too.

Adding swiftlint as a pre-commit hook should solve this issue.