Update crates/spirv-builder/README.md

Co-authored-by: Eduard-Mihai Burtescu <[email protected]>

Author: 2 people

crates/spirv-builder/README.md

@@ -13,11 +13,11 @@ It takes care of pulling in the `SPIR-V` backend for Rust, `rustc_codegen_spirv`
 ```rust
 use spirv_builder::{MetadataPrintout, SpirvBuilder};
 
-fn main() {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     SpirvBuilder::new("my_shaders", "spirv-unknown-vulkan1.1")
         .print_metadata(MetadataPrintout::Full)
-        .build()
-        .unwrap(); 
+        .build()?;
+    Ok(())
 }
 ```