Update index.mdx (#2230)

Author: sanposhiho

docs/src/docs/usage/install/index.mdx

@@ -106,7 +106,11 @@ Note: such `go get` installation aren't guaranteed to work. We recommend using b
 <div style="margin-top: 2em;">
 
 ```sh
-go get github.com/golangci/golangci-lint/cmd/golangci-lint@{.LatestVersion}
+# Go 1.16+
+go install github.com/golangci/golangci-lint/cmd/golangci-lint@{.LatestVersion}
+
+# Go version < 1.16
+go get -u github.com/golangci/golangci-lint/cmd/golangci-lint@{.LatestVersion}
 ```
 
 </div>