Add a link for how to manage the chrome network bug triage rotation.

Change-Id: I7d9ca04bc1c82a0a7341bd76dd265653cb0fba55
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1575162Reviewed-by: Ryan Hamilton <rch@chromium.org>
Commit-Queue: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652686}

net/docs/bug-triage.md

@@ -4,6 +4,12 @@ The Chrome network team uses a two day bug triage rotation.  The main goals are
 to identify and label new network bugs, and investigate network bugs when no
 label seems suitable.
 
+## Management
+
+Owners for the network bug triage rotation can find instructions on
+generating and modifying shifts
+[here (internal-only)](https://goto.google.com/pflvb).
+
 ## Responsibilities
 
 ### Required, in rough order of priority: