Heading level for Changelog entries

[GaryJ]

In the new plugin repo, the plugin name is h1 (good), the section headings such as Description, Screenshots, Reviews, Changelog are h2 (good), and each Review title is a h3 (good).

However, each Changelog entry heading (i.e. version + date) jumps straight to a h4, despite the parent heading being a h2.

For the sake of structured hierarchical headings for screen reader users, I'd expect these change log entries to have h3 headings, even if it also had a class to style it as a smaller font (unnecessary IMO, but it's a better solution than skipped headings).

[GaryJ]

Highlights the issue, with the v3.0 release edited in browser dev tools to display as a h3 instead of the default h4.

[dd32]

This is an unfortunate side effect of the markdown parsing, which doesn't allow us to easily change the header style for elements - it's based on what heading level was specified in the markdown.

For screen readers, we shouldn't skip levels, but due to the complexity i'm lowering the priority.