README.md: Update waterfall location

Bug: 860896
TBR: thestig
Change-Id: I61208b951e3746dae363f91dc9eab2319378b48f
Reviewed-on: https://pdfium-review.googlesource.com/38895
Reviewed-by: Ryan Tseng <hinoka@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Ryan Tseng <hinoka@google.com>
diff --git a/README.md b/README.md
index dd6224e..0312fbc 100644
--- a/README.md
+++ b/README.md
@@ -151,7 +151,7 @@
 ## Waterfall
 
 The current health of the source tree can be found at
-http://build.chromium.org/p/client.pdfium/console
+https://ci.chromium.org/p/pdfium/g/main/console
 
 ## Community