add some files to git ignore and test npm package

Signed-off-by: Winner95 <Winner95@users.noreply.github.com>

Author: Winner95

.gitignore

@@ -1 +1,3 @@
+.DS_Store
+coverage
 node_modules

package.json

@@ -2,6 +2,11 @@
   "name": "typescript-react-function-component-props-handler",
   "version": "1.1.1",
   "description": "a custom react function components props handler for react-docgen. It allows you to parse props, which are typed as React.functionComponent<props> without rewriting your code",
+  "files": [
+    "index.js",
+    "README.md",
+    "LICENSE"
+  ],
   "main": "index.js",
   "scripts": {
     "test": "jest",