update README for API keys (#7933)
update README for API keys (#7933)

update README for API keys
rsudev/c-geo-opensource,S-Bartfast/cgeo,auricgoldfinger/cgeo,cgeo/cgeo,cgeo/cgeo,cgeo/cgeo,auricgoldfinger/cgeo,rsudev/c-geo-opensource,tobiasge/cgeo,S-Bartfast/cgeo,S-Bartfast/cgeo,tobiasge/cgeo,matej116/cgeo,matej116/cgeo,rsudev/c-geo-opensource,auricgoldfinger/cgeo,tobiasge/cgeo,cgeo/cgeo,matej116/cgeo