Removed upgrade in public with mike 2.1.3

public/upgrade/media/SDT_4_0_basic_elements.png

public/upgrade/media/binarySwitch.svg

public/upgrade/media/deviceAirConditioner.svg

public/upgrade/media/lifecycle_of_a_dmfirmware_1.svg

public/upgrade/media/lifecycle_of_a_dmfirmware_2.svg

public/upgrade/media/logo.png

public/upgrade/media/toggle.svg

public/upgrade/search/search_index.json

public/upgrade/sitemap.xml

public/upgrade/sitemap.xml.gz

public/upgrade/stylesheets/extra.css

public/versions.json