quickjs repo HEAD should be match with downloaded wasmedge_quickjs.wasm

Author: hiroshi

docs/develop/javascript/hello_world.md

@@ -20,6 +20,7 @@ Then download the pre-built WasmEdge QuickJS Runtime program, and optionally, AO
 ```bash
 curl -OL https://github.com/second-state/wasmedge-quickjs/releases/download/v0.5.0-alpha/wasmedge_quickjs.wasm
 wasmedge compile wasmedge_quickjs.wasm wasmedge_quickjs.wasm
+git checkout v0.5.0-alpha
 ```
 
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