validate FRAME-RATE is exactly 59.94 (#70)

previously only the 720p60 line had the FRAME-RATE key. But now all
qualities contain the key, so we need to be more specific and check if
the key is for 59.94 (60hz)

Author: tarkah

src/stream.rs

@@ -500,10 +500,10 @@ fn get_quality_link(
             let quality_str: &str = quality.into();
             let quality_check = format!("x{}", quality_str);
 
-            if (quality == Quality::_720p60 && line.contains("FRAME-RATE"))
+            if (quality == Quality::_720p60 && line.contains("FRAME-RATE=59.94"))
                 || (quality != Quality::_720p60
                     && line.contains(&quality_check)
-                    && !line.contains("FRAME-RATE"))
+                    && !line.contains("FRAME-RATE=59.94"))
             {
                 available_qualities.push((quality, idx));
                 continue;