libmysqlclient-dev is now default-mylibsqlclient-dev
libmysqlclient-dev is now default-mylibsqlclient-dev

Dockerfile: update package name for final apt-get install

Also cosmetics; add missing newline to sources.list.d/yarn.list

Charcoal-SE/metasmoke,j-f1/forked-metasmoke,Charcoal-SE/metasmoke,Charcoal-SE/metasmoke,j-f1/forked-metasmoke,j-f1/forked-metasmoke,Charcoal-SE/metasmoke,j-f1/forked-metasmoke