[build] Update DEPS to reference new catapult repo location

This ports:
https://chromium-review.googlesource.com/c/chromium/src/+/688742

TBR=agable@chromium.org

Bug: chromium:731091
Change-Id: I99b6bfcc769a5f3c429668c2d36518bcac80f3cf
Reviewed-on: https://chromium-review.googlesource.com/692634Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48236}

DEPS

@@ -48,7 +48,7 @@ deps_os = {
     "v8/third_party/android_tools":
       Var("chromium_url") + "/android_tools.git" + "@" + "aadb2fed04af8606545b0afe4e3060bc1a15fad7",
     "v8/third_party/catapult":
-      Var('chromium_url') + "/external/github.com/catapult-project/catapult.git" + "@" + "9a255f51046c55ea3c209acd64e36d8a5bd46fa4",
+      Var('chromium_url') + "/catapult.git" + "@" + "9a255f51046c55ea3c209acd64e36d8a5bd46fa4",
   },
 }