ddtrace/tracer: replace Windows path characters in fake UDS host (#1713)

We still need to give a full URL to the HTTP client, with the "http"
scheme, but we want the URL to somewhat resemble the UDS path. Windows
paths contain colons and back-slashes. Colons in particular cause
trouble because they're usually followed by a port. Replace those
characters with something else.

ddtrace/tracer/option.go

@@ -230,7 +230,7 @@ func newConfig(opts ...StartOption) *config {
 		c.httpClient = udsClient(c.agentURL.Path)
 		c.agentURL = &url.URL{
 			Scheme: "http",
-			Host:   fmt.Sprintf("UDS_%s", strings.ReplaceAll(c.agentURL.Path, "/", "_")),
+			Host:   fmt.Sprintf("UDS_%s", strings.NewReplacer(":", "_", "/", "_", `\`, "_").Replace(c.agentURL.Path)),
 		}
 	} else if c.httpClient == nil {
 		c.httpClient = defaultClient