Change the doc

specs/README.md

@@ -24,13 +24,19 @@ Use `spectrum` to create the Postman 2.x collection from the OpenAPI 3 API Speci
 
 ### Installation
 
-The following will install the `spectrum` executable in the `~/go/bin` directory.
+Be sure to have the version of go specified in the go.mod file. If you have the latest version of go installed, you can install an oldest version with :
 
 ```bash
-$ go install github.com/grokify/[email protected]
+$ go install golang.org/dl/go1.16@latest
 ```
 
-This approach requires `go` 1.16 be installed on your system. See more here: [https://golang.org/](https://golang.org/).
+See more here: [https://golang.org/](https://golang.org/).
+
+The following will install the `spectrum` executable in the `~/go/bin` directory.
+
+```bash
+$ ~/go/bin/go1.16 install github.com/grokify/[email protected]
+```
 
 ### Usage