internal/scan: trim the newlines off the GoVersion

Fixes golang/go#61330

Change-Id: I778cec302f71baeb3b7d3ddb4fdbf492f5079bf2
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/509275
Run-TryBot: Ian Cottrell <iancottrell@google.com>
Reviewed-by: Julie Qiu <julieqiu@google.com>
Auto-Submit: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

Author: ianthehat

internal/scan/run.go

@@ -82,7 +82,7 @@ func prepareConfig(ctx context.Context, cfg *config, client *client.Client) {
 		}
 		if cfg.GoVersion == "" {
 			if out, err := exec.Command("go", "env", "GOVERSION").Output(); err == nil {
-				cfg.GoVersion = string(out)
+				cfg.GoVersion = strings.TrimSpace(string(out))
 			}
 		}
 	}