Finding swift project root by *.xcodeproj directory location

## Information

**VIM version**

NVIM v0.10.2
Build type: Release
LuaJIT 2.1.1727870382

Operating System: MacOS

## What went wrong

Swift project root can not be detected when using `sourcekitlsp` linter for XCode project.
As per source code, the project root is searched by location of `Package.swift` file which is only present for swift library but not for swift app.
The swift app is defined by location of `*.xcodeproj` directory or `*.xcworkspace` directory.

## Reproducing the bug

``` viml
let b:ale_linters=["sourcekitlsp"]
```

### :ALEInfo

```
LSP Error Messages:

(Errors for sourcekitlsp)
Failed to find project root, language server won't start.
```

Start with ALE's sourcekitlsp root detection and its reported search for Package.swift. Reproduce using let b:ale_linters=["sourcekitlsp"] in an Xcode app project and inspect :ALEInfo. Done means roots containing *.xcodeproj or *.xcworkspace directories are recognized without breaking Package.swift detection, and the reported root error no longer prevents server startup. No implementation files or tests are named; the issue has gone 646 days without a response.

Written by the indexing model from the issue text.