Rust-GPU: pin to 985007fc, until i can figure how to bump it

crates/spirv_backend/Cargo.toml

@@ -7,5 +7,5 @@ edition = "2021"
 crate-type = ["dylib", "lib"]
 
 [dependencies]
-spirv-std = { git = "https://github.com/Rust-GPU/rust-gpu", features = ["glam"] }  # MIT or Apache 2.0
+spirv-std = { git = "https://github.com/Rust-GPU/rust-gpu", rev = "985007fc", features = ["glam"] }  # MIT or Apache 2.0
 coremem_cross = { path = "../cross" }