chore: update location of js_protocol.pdl (#108)

* chore: update location of js_protocol.pdl

Chromium changed the location of js_protocol.pdl:
https://chromium-review.googlesource.com/c/chromium/src/+/1665929

* Use v8_inspector_js_protocol to find pdl file

src/inspector/BUILD.gn

@@ -156,7 +156,7 @@ generate_protocol_json("node_protocol_json") {
 
 generate_protocol_json("v8_protocol_json") {
   sources = [
-    "//v8/src/inspector/js_protocol.pdl",
+    v8_inspector_js_protocol,
   ]
   outputs = [
     "$target_gen_dir/js_protocol.json",