Bump github.com/apple/swift-docc-plugin from 1.3.0 to 1.4.3 (#101)

Bumps [github.com/apple/swift-docc-plugin](https://github.com/apple/swift-docc-plugin) from 1.3.0 to 1.4.3.
- [Release notes](https://github.com/apple/swift-docc-plugin/releases)
- [Commits](swiftlang/swift-docc-plugin@1.3.0...1.4.3)

---
updated-dependencies:
- dependency-name: github.com/apple/swift-docc-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Package.swift

@@ -22,7 +22,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/space-code/concurrency.git", exact: "0.1.0"),
-        .package(url: "https://github.com/apple/swift-docc-plugin", exact: "1.3.0"),
+        .package(url: "https://github.com/apple/swift-docc-plugin", exact: "1.4.3"),
         .package(url: "https://github.com/space-code/log.git", exact: "1.2.0"),
         .package(url: "https://github.com/space-code/atomic.git", exact: "1.1.0"),
         .package(