Update image URLs to use kubevela.io for consistency#1376

FogDong merged 3 commits intokubevela:mainkubevela/kubevela.github.io:mainfrom

vishal210893:chore/update-url-for-tls-errorvishal210893/kubevela.github.io:chore/update-url-for-tls-errorCopy head branch name to clipboard