capture std err when getting required plugins for go (#4141)

* capture std err when getting required plugins for go

CHANGELOG.md

@@ -4,6 +4,8 @@ CHANGELOG
 ## HEAD (unreleased)
 - Move to a multi-module repo to enable modules for the Go SDK
   [#4109](https://github.com/pulumi/pulumi/pull/4109)
+- Report compile time errors for Go programs during plugin acquisition.
+  [#4141](https://github.com/pulumi/pulumi/pull/4141)
 
 ## 1.13.0 (2020-03-18)
 - Add support for plugin acquisition for Go programs

sdk/go/pulumi-language-go/main.go

@@ -167,6 +167,7 @@ func (host *goLanguageHost) GetRequiredPlugins(ctx context.Context,
 
 	cmd.Env = os.Environ()
 	cmd.Env = append(cmd.Env, "PULUMI_PLUGINS=true")
+	cmd.Stderr = os.Stderr
 
 	stdout, err := cmd.Output()
 	if err != nil {