Add files to package.json and update description

Author: vweevers

.npmignore

@@ -1,6 +1,6 @@
 # level-packager
 
-> `levelup` package helper for distributing with an `abstract-leveldown` compatible back-end
+> `levelup` package helper for distributing with an `abstract-leveldown` store.
 
 [![level badge][level-badge]](https://github.com/Level/awesome)
 [![npm](https://img.shields.io/npm/v/level-packager.svg?label=&logo=npm)](https://www.npmjs.com/package/level-packager)

README.md

@@ -1,5 +1,6 @@
 'use strict'
 
 const path = require('path')
+const os = require('os')
 
-module.exports = path.join(__dirname, 'level-test-' + process.pid + '.db')
+module.exports = path.join(os.tmpdir(), 'level-packager-' + process.pid + '-' + Date.now())

abstract/location.js

@@ -1,7 +1,7 @@
 {
   "name": "level-packager",
   "version": "5.1.1",
-  "description": "LevelUP package helper for distributing with a LevelDOWN-compatible back-end",
+  "description": "levelup package helper for distributing with an abstract-leveldown store",
   "license": "MIT",
   "main": "level-packager.js",
   "scripts": {
@@ -11,6 +11,14 @@
     "dependency-check": "dependency-check . test.js abstract/*.js",
     "prepublishOnly": "npm run dependency-check"
   },
+  "files": [
+    "abstract",
+    "level-packager.js",
+    "CHANGELOG.md",
+    "CONTRIBUTORS.md",
+    "LICENSE.md",
+    "UPGRADING.md"
+  ],
   "dependencies": {
     "encoding-down": "^6.3.0",
     "levelup": "^4.3.2"