updating_clang.md: Add win-asan to the list of tryjobs

Bug: none
Change-Id: I7c267cf630c6e8ee29bbf39b295adc6c9e4bbd93
Reviewed-on: https://chromium-review.googlesource.com/1252589Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595427}

docs/updating_clang.md

@@ -52,7 +52,8 @@ An archive of all packages built so far is at https://is.gd/chromeclang
     git cl try -B luci.chromium.try -b ios-device -b mac_chromium_asan_rel_ng \
       -b linux_chromium_cfi_rel_ng \
       -b linux_chromium_chromeos_asan_rel_ng -b linux_chromium_msan_rel_ng \
-      -b linux_chromium_chromeos_msan_rel_ng -b linux-chromeos-dbg
+      -b linux_chromium_chromeos_msan_rel_ng -b linux-chromeos-dbg \
+      -b win-asan
     ```
 
 1.  Optional: Start Pinpoint perf tryjobs. These are generally too noisy to