adding an `.npmignore` file
adding an `.npmignore` file

should slightly help speed up `npm i` time, and is generally a good practice

reggi/node-fs-extra,jprichardson/node-fs-extra,Narigo/node-fs-extra,KoryNunn/node-fs-extra,SciSpike/node-fs-extra,snuggles08/node-fs-extra,JanMattner/node-fs-extra