fix: change cargo lib and bin path to enable build on WSL

[michidk]

The project cannot be cross-compiled on Linux, because the file paths are in a format which is supported by Windows only:

[lib]
path = "src\\lib.rs"

[[bin]]
name = "glazewm"
path = "src\\main.rs"

Changing \\ to / fixes the issue and works both, on Linux and on Windows.

Motivation: My whole developer workflow is on WSL. My typical workflow is to build on WSL and then test on Windows.

How to build glazewm on Ubuntu:

(assuming this patch is applied and nightly is setup already)

1. Install dependencies: sudo apt-get update; sudo apt-get install libgtk-3-dev librust-atk-dev
2. Add windows (gnu) target: rustup target add x86_64-pc-windows-gnu
3. Finally, build the project: cargo build --target x86_64-pc-windows-gnu

[github-actions]

🎉 This PR is included in version 3.6.0 🎉

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[github-actions]

🎉 This PR is included in version 3.6.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀