Fixed warnings reported by SwiftLint

[jguz-pubnub]

• Trailing whitespaces
  • https://realm.github.io/SwiftLint/trailing_whitespace.html
• Moving let keyword out of tuples
  • https://realm.github.io/SwiftLint/pattern_matching_keywords.html
• Operator whitespace
  • https://realm.github.io/SwiftLint/operator_whitespace.html
• Fixed usage of master keyword in Example-iOS target
  • https://realm.github.io/SwiftLint/inclusive_language.html
• Disabling force unwrapping rule in some unit tests
  • https://realm.github.io/SwiftLint/force_unwrapping.html
• Empty parameters
  • https://realm.github.io/SwiftLint/empty_parameters.html
• Empty Parentheses with Trailing Closure
  • https://realm.github.io/SwiftLint/empty_parentheses_with_trailing_closure.html
• Using private over fileprivate
  • https://realm.github.io/SwiftLint/private_over_fileprivate.html
• For-Where in AnyJSONType.swift, line 372
  • https://realm.github.io/SwiftLint/for_where.html
• Removed force unwrapping in CryptoInputStream
  • https://realm.github.io/SwiftLint/force_unwrapping.html
• Invalid SwiftLint Command
  • https://realm.github.io/SwiftLint/invalid_swiftlint_command.html
• Unneeded Overridden Functions
  • https://realm.github.io/SwiftLint/invalid_swiftlint_command.html
• Applied recommended settings by Xcode and upgrading macOS deployment target from 10.13 to 10.15

[parfeon]

LGTM!