Renamed package name.

README.md

 
 ```javascript
 // Import convert module
-const document = require("document-convert");
+const document = require("file-convert");
 
 const options = {
   libreofficeBin: "C:\\Program Files\\LibreOffice\\program\\soffice.exe",

package.json

 {
-  "name": "document-convert",
+  "name": "file-convert",
   "version": "1.0.0",
   "description": "The package export ppt, pptx, odp and key files to pdf and/or img(png, jpg, jpeg and etc...).",
   "main": "index.js",
   "keywords": [
     "ppt to pdf",
     "pptx to pdf",
-    "keynote to",
+    "keynote to pdf",
     "odp to image",
     "ppt to image",
     "pptx to image",
-    "keynote image",
+    "keynote to image",
     "odp to image",
     "pdf to image",
     "imagemagick",