use h4 instead of unordered list

Please check if the PR fulfills these requirements

[x] The branch naming convention follows our guidelines
[ ] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Enhancement

What is the current behavior? (You can also link to an open issue here)

The pull request template currently used relies on unordered list items for each section, and this makes writing a PR a bit messy when using lists in those sections.

What is the new behavior (if this is a feature change)?

Unordered list items are being replaced with H4, an example is the following PR written using the new template.

The following list is an example:

item 1
item 2
1. subitem
2. subitem
3. subitem
item 3

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

None

Other information: