how to add swiftlint to third party packages

To add SwiftLint to third-party packages, you can follow these general steps:

Add SwiftLint as a Dependency: You need to add SwiftLint as a dependency in your Package.swift file. This can be done by including it in the dependencies array.

// swift-tools-version:5.3
import PackageDescription

let package = Package(
    name: "YourPackageName",
    dependencies: [
        .package(url: "https://github.com/realm/SwiftLint.git", from: "0.43.0")
    ],
    targets: [
        .target(
            name: "YourTargetName",
            dependencies: ["SwiftLint"]
        )
    ]
)

Configure SwiftLint: Create a .swiftlint.yml file in the root of your package to configure the rules and settings for SwiftLint.

disabled_rules: # rule identifiers to exclude from running
  - line_length
  - type_name

opt_in_rules: # some rules are only opt-in
  - empty_count
  - missing_docs

included: # paths to include during linting. `--path` is ignored if present.
  - Source

excluded: # paths to ignore during linting. Takes precedence over `included`.
  - Carthage
  - Pods

Run SwiftLint: You can run SwiftLint manually from the command line or integrate it into your build process. To run it manually, navigate to your package directory and execute:
```
swift run swiftlint
```
Integrate with Xcode: If you are using Xcode, you can add a build phase to run SwiftLint automatically. Go to your Xcode project settings, select your target, and add a new "Run Script Phase" with the following script:
```
if which swiftlint >/dev/null; then
  swiftlint
else
  echo "warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint"
fi
```

For more detailed information on working with Swift packages, you can refer to the session A Swift Tour: Explore Swift’s features and design.