Release 6.1.0.beta

[jamescarr28]

Release notes

Bugfix for active tabs

This bug fix:

• fixes an issue where some a nested structure can cause header_links to be incorrectly set or unset as 'active'
• adds a new test suite to clearly test and define the expected behaviour of the active tab

Enable GOV.UK Design System components

This enhancement:

• adds a nunjucks render extension to allow calling and rendering of GOV.UK components
• adds an option configuration to enable this extension