Template not copied when installing with YARN

[gonzochic]

When installing with yarn:
yarn add --dev apidoc-markdown2 not all files from the templates directory are copied to the according node_modules/apidoc-markdown2/templates folder (the default.md is missing).

When using npm install --dev apidoc-markdown2 the file is there.

Using:
Node v8.1.3
Yarn 0.27.5
NPM 5.0.3

The file is required when I want to run apidoc -i lib/ -o apidoc/ && apidoc-markdown2 -p apidoc/ -o apidoc/api_doc.md

Cheers

[softdevstory]

I don't use yarn, now.

If you can find reason and send me a patch, I will merge it :)