chore(npm): improve ignore list (#51)

diff --git a/.npmignore b/.npmignore
index d71cbd7..45e3c38 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,16 +1,3 @@
-# CI service configurations
-.travis.yml
-.appveyor.yml
+.*
 appveyor.yml
-
-# Testing, code coverage, and linting
-.eslintignore
-.eslintrc.yml
-
-# Git
-.git
-.gitattributes
-.gitignore
-
-# Github
-.github
+tests