Add Dawn to projects for my_activity.py

Change-Id: Id22cde5b5c113fb1145c30afb6671ac2ec32afb1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1819547
Auto-Submit: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>

my_activity.py

@@ -90,6 +90,9 @@ gerrit_instances = [
     'shorturl': 'crrev.com/c',
     'short_url_protocol': 'https',
   },
+  {
+    'url': 'dawn-review.googlesource.com',
+  },
   {
     'url': 'pdfium-review.googlesource.com',
   },
@@ -107,13 +110,14 @@ monorail_projects = {
     'shorturl': 'crbug.com',
     'short_url_protocol': 'https',
   },
+  'dawn': {},
   'google-breakpad': {},
   'gyp': {},
-  'skia': {},
   'pdfium': {
     'shorturl': 'crbug.com/pdfium',
     'short_url_protocol': 'https',
   },
+  'skia': {},
   'v8': {
     'shorturl': 'crbug.com/v8',
     'short_url_protocol': 'https',