Add changelog link to plugin meta

[szepeviktor]

Description

Cautious webmasters need to take a look at the changelog.

Type of change

• New feature (non-breaking change which adds functionality).
• Bug fix (non-breaking change which fixes an issue).
• Enhancement (non-breaking change which improves an existing functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as before).
• Sub-task of #(issue number)
• Chore
• Release