changed guide highlighting to shell (#1593)

roz3x · web-flow · commit de3a2d4df33d · 2020-06-30T21:08:30.000-07:00
diff --git a/README.md b/README.md
@@ -52,7 +52,7 @@ Lower is better!
 
 ### Installation
 
-```go
+```sh
 // go get github.com/labstack/echo/{version}
 go get github.com/labstack/echo/v4
 ```
