Fix formatting and wording in README.md

[iArxic]

"the the" 🤔

Before this PR

found a very minor mistake here

After this PR

Fix formatting and wording in README.md

Possible downsides?

[palantirtech]

Thanks for your interest in palantir/gradle-plugin-testing, @iArxic! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[changelog-app]

Generate changelog in changelog/@unreleased

Type (Select exactly one)

• Feature (Adding new functionality)
• Improvement (Improving existing functionality)
• Fix (Fixing an issue with existing functionality)
• Break (Creating a new major version by breaking public APIs)
• Deprecation (Removing functionality in a non-breaking way)
• Migration (Automatically moving data/functionality to a new system)

Description

Fix formatting and wording in README.md

Check the box to generate changelog(s)

• Generate changelog entry