New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues
  • Run SwiftLint with custom configuration on multiple files #3038 is similar, but not the same

Describe the bug

Assume a file exists called Path/To/My/File.swift, and assume Path/To/My is a directory that contains a .swiftlint.yml file. When you tell SwiftLint to lint only the file, it uses the default configuration instead of the YAML file in Path/To/My.

I believe the root cause is due to these lines, which return the default configuration immediately instead of checking the directory for any configurations.

Complete output when running SwiftLint, including the stack trace and command used

$ swiftlint lint -- Path/To/My/File.swift

Environment

• SwiftLint version (run swiftlint version to be sure)? 0.40.2
• Installation method used (Homebrew, CocoaPods, building from source, etc)? Homebrew
• Paste your configuration file:

disabled_rules:
    - cyclomatic_complexity
    - force_cast
    - function_body_length

• Are you using nested configurations?
  Yes, see above.
• Which Xcode version are you using (check xcodebuild -version)?
  Xcode 11.7
  Build version 11E801a
• Do you have a sample that shows the issue? Run echo "[string here]" | swiftlint lint --no-cache --use-stdin --enable-all-rules
  to quickly test if your example is really demonstrating the issue. If your example is more
  complex, you can use swiftlint lint --path [file here] --no-cache --enable-all-rules.
  See above.

// This triggers a violation:
let foo = "Test" as! Array