fix(conventional-changelog-conventionalcommits)!: use ## <small> for patch versions

[shivjm]

This is a backwards-incompatible change, so I would understand if it needed to be behind a configuration flag or something. I’ll leave it open pending feedback (or merging, of course!).

Closes #867

EDIT:
I got the tests running but they universally fail even on a clean upstream clone inside a Docker container, so I don’t think they’ll be much help here.

[languitar]

Would it also be an option to go in this direction regarding my comment at #867 (comment) ?

diff --git a/packages/conventional-changelog-conventionalcommits/templates/header.hbs b/packages/conventional-changelog-conventionalcommits/templates/header.hbs
index a4d6ec4..d7efc8f 100644
--- a/packages/conventional-changelog-conventionalcommits/templates/header.hbs
+++ b/packages/conventional-changelog-conventionalcommits/templates/header.hbs
@@ -1,8 +1,4 @@
-{{#if isPatch~}}
-  ###
-{{~else~}}
-  ##
-{{~/if}} {{#if @root.linkCompare~}}
+## {{#if @root.linkCompare~}}
   [{{version}}]({{compareUrlFormat}})
 {{~else}}
   {{~version}}

[shivjm]

Sure. I used small to preserve the appearance like in #214, but since the element has its own semantics I’d be happier leaving it out.

[shivjm]

I guess #920 supersedes this.