Bug 1558271 - Add browsertime-results to hgignore r=nalexander

browsertime-results is the default output directory for mach browsertime.  It should be part of hgignore to not clutter the workspace.

Differential Revision: https://phabricator.services.mozilla.com/D34389

--HG--
extra : moz-landing-system : lando

.hgignore

@@ -193,5 +193,8 @@ tps_result\.json
 ^testing/raptor/raptor/tests/.*.json
 ^testing/raptor/webext/raptor/auto_gen_test_config.js
 
+# Ignore browsertime output directory
+^browsertime-results
+
 # Ignore the build directories of WebRender standalone builds.
 gfx/wr/target/