make spirv-std git repo lowercase

Author: Firestar99

Cargo.lock

@@ -70,7 +70,7 @@ axum = "0.8"
 chrono = "0.4"
 ron = "0.8"
 fastnoise-lite = "1.1"
-spirv-std = { git = "https://github.com/Rust-GPU/rust-gpu", rev = "9a357691334b9cdd13c82a740ced97c5d857bf4d" }
+spirv-std = { git = "https://github.com/rust-gpu/rust-gpu", rev = "9a357691334b9cdd13c82a740ced97c5d857bf4d" }
 wgpu-types = "23"
 wgpu = "23"
 once_cell = "1.13" # Remove when `core::cell::LazyCell` (<https://doc.rust-lang.org/core/cell/struct.LazyCell.html>) is stabilized in Rust 1.80 and we bump our MSRV