Bump version (v0.55.6)

Merge pull request brave#1131 from brave/70.0.3538.16

Upgrade to Chromium 70.0.3538.16

Merge pull request brave#1104 from brave/cli-disable-brave-rewards-ex…

…tension

Add CLI arg for starting without Brave Rewards extension

Merge pull request brave#1094 from srirambv/srirambv-patch-1

Fix about version info

Merge pull request brave#860 from brave/copy_brave_appearance_page_mo…

…dule

Copy brave_appearance_page module

Merge pull request brave#860 from brave/copy_brave_appearance_page_mo…

…dule

Copy brave_appearance_page module

Merge pull request brave#734 from brave/vmodule

Support --vmodule for verbose logging from specific modules

Merge pull request brave#734 from brave/vmodule

Support --vmodule for verbose logging from specific modules

Merge pull request brave#870 from brave/start-flag-ui_mode

support ui_mode cli flag for start command

Merge pull request brave#835 from brave/70.0.3528.4

Upgrade to Chromium 70.0.3528.4