Adds a definition to "unit test" in the tech dictionary

[avinashi10]

This PR fixes...

The missing "unit test" definition in the Tech Dictionary

What I did...

• Added a definition to the dictionary entry "unit test"
• Added a source url for the definition

How to test...

1. In your local repo, from the pit branch, fetch the latest changes with git fetch and git pull (First refer to https://github.com/cherryontech/website/blob/pit/README.md if you have not yet cloned the repo locally).
2. Switch to the branch containing this change with git switch unitTestDictionary
3. Run npm install or yarn install
4. Run gridsome develop to start a local dev server. In the terminal, you will see an address such as http://localhost:8080/. Navigate to that address in a browser.
5. Navigate to the Dictionary page and search for "unit test" or scroll down to the "unit test" entry (NOTE: this is a different entry than "Unit testing")
6. Ensure that you can see the definition of unit test and that the definition makes sense

I learned...

I got to see a bit of how Gridsome and VueJS work!

[alliequintano]

Try removing the package-lock.json and yarn.lock files from your PR and we'll see if that resolves the build errors 👍