Update build bot update instructions (#20301)

`run_recipe.py` has been removed and waterfall is deprecated...

dev/bots/README.md

@@ -3,7 +3,7 @@
 This directory exists to support building Flutter on our build infrastructure.
 
 The results of such builds are viewable at:
-* https://build.chromium.org/p/client.flutter/waterfall
+* https://build.chromium.org/p/client.flutter/console
 * https://travis-ci.org/flutter/flutter/builds (limited checking used just for PRs on github)
 
 The external master pages for the chromium infra bots do not allow
@@ -63,7 +63,7 @@ The typical cycle for editing a recipe is:
    `//chrome_infra/build/scripts/slave/recipes/flutter`).
 2. Run `build/scripts/slave/recipes.py --use-bootstrap test train` to
    update expected files
-3. Run `build/scripts/tools/run_recipe.py flutter/<repo> slavename=<slavename>
+3. Run `build/scripts/slave/recipes.py run flutter/<repo> slavename=<slavename>
    mastername=client.flutter buildername=<buildername> buildnumber=1234` where `<repo>` is one
    of `flutter` or `engine`, and `slavename` and `buildername` can be looked up
    from the *Build Properties* section of a [recent