Added attributionsrc attributes

https://wicg.github.io/attribution-reporting-api/#monkeypatch-attributionsrc

leak.html

@@ -137,6 +137,7 @@
 %Links & Maps
 -->
 <a ping="https://leaking.via/a-ping" href="#">You have to click me</a>
+<a attributionsrc="foo bar https://leaking.via/a-attributionsrc" href="#">You have to click me</a>
 <img src="data:;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw" width="150" height="150" usemap="#map">
 <map name="map">
   <area ping="https://leaking.via/area-ping" shape="rect" coords="0,0,150,150" href="#">
@@ -164,7 +165,8 @@
 <img dynsrc="https://leaking.via/img-dynsrc">
 <img lowsrc="https://leaking.via/img-lowsrc">
 <img src="data:image/svg+xml,<svg%20xmlns='%68ttp:%2f/www.w3.org/2000/svg'%20xmlns:xlink='%68ttp:%2f/www.w3.org/1999/xlink'><image%20xlink:hr%65f='%68ttps:%2f/leaking.via/svg-via-data'></image></svg>">
-
+<img attributionsrc="foo bar https://leaking.via/img-attributionsrc">
+
 <image src="https://leaking.via/image-src">
 <image href="https://leaking.via/image-href">
 
@@ -237,6 +239,7 @@
 %Script
 -->
 <script src="https://leaking.via/script-src"></script>
+<script attributionsrc="foo bar https://leaking.via/script-attributionsrc"></script>
 <svg><script href="https://leaking.via/svg-script-href"></script></svg>
 <svg><script xlink:href="https://leaking.via/svg-script-xlink-href"></script></svg>
 <script>