[Fix]: Publish the package on NPM

Before this commit it was required to install the package
using Github. However when using NPM version 8.5, the installation
used to fail with the following error :
"... git --no-replace-objects clone https://git@github.com/ElucidataInc/node-s3-client.git
 /root/.npm/_cacache/tmp/git-cloneNZtpAU --recurse-submodules
npm ERR! fatal: could not create leading directories of
'/root/.npm/_cacache/tmp/git-cloneNZtpAU': Permission denied"

The following Github threads were reported with similar issues
- npm/cli#624
- npm/cli#642

As the suggested methods in the above threads, like shifting to older
version of NPM, did not satisfy our needs, we are publishing the package
to NPM public registry

.npmignore

@@ -1,2 +1,3 @@
 /node_modules
 /test
+.idea

package.json

@@ -6,6 +6,10 @@
   "scripts": {
     "test": "mocha"
   },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org/"
+  },
   "repository": {
     "type": "git",
     "url": "https://github.com/ElucidataInc/node-s3-client.git"