Update screenshot.rs

Fixed an issue with illegal characters in windows filenames

Author: enomothem

src/cli/screenshot.rs

@@ -144,7 +144,7 @@ async fn take_screenshot(
         .trust_dns(true)
         .build()?;
 
-    let filename = format!("{}.png", url.replace("://", "-").replace('/', "_"));
+    let filename = format!("{}.png", url.replace("://", "-").replace('/', "_").replace(':', "-"));
     let page = browser.new_page(parsed_url.clone()).await?;
     page.save_screenshot(
         ScreenshotParams::builder()