Improved CONTRIBUTING.md

[forkbikash]

Issue Number

fixes #363

Describe the changes you've made

1. Space addition between 'repository' and 'new-issue' in CONTRIBUTING.md.

2. Included 6th point as 'Type the command cd edu-client and hit enter.' in Clone repository section of the CONTRIBUTING.md file.

Describe if there is any unusual behavior (Any Warning) of your code(Write NA if there isn't)

NA

Checklist

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] All new and existing tests passed.
• [x] The title of my pull request is a short description of the requested changes.