circleci: Remove resource_class, which CircleCI no longer supports
circleci: Remove resource_class, which CircleCI no longer supports

thewtex/cross-compilers,dockcross/dockcross,dockcross/dockcross,dockcross/dockcross,thewtex/cross-compilers,thewtex/cross-compilers,dockcross/dockcross,thewtex/cross-compilers