docs: adds Git and NPM prerequisites to README

Specify that you must have Git and NPM installed in order continue installing and properly run the NerdPack.

README.md

@@ -49,8 +49,14 @@ Personal access tokens are stored with New Relic One's `UserStorage`
 APIs. `UserStorage` data is accessible only to the user account and `Nerdpack` which created it. The data is encrypted in transmission, but is not encrypted at rest (within the underlying database). Because of this, `UserStorage` data may be accessible to a New Relic employee via an administrative privilege in the platform.
 
 ## Getting started
+First, ensure that you have [Git](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git) and [NPM](https://www.npmjs.com/get-npm) installed. If you're unsure whether you have one or both of them installed, run the following command(s) (If you have them installed these commands will return a version number, if not, the commands won't be recognized):
 
-Clone this repository and run the following scripts:
+```bash
+git --version
+npm -v
+```
+
+Next, clone this repository and run the following scripts:
 
 ```bash
 nr1 nerdpack:clone -r https://github.com/newrelic/nr1-github.git