CHANGELOG.md versions have wrong markdown

[euri10]

Discussed in #1388

^{Originally posted by HarrySky February 23, 2022}
Hey, just noticed, that Renovate can't parse your CHANGELOG.md since 0.17.4 version 😅

You seem to have wrong title style applied

Actual:

### 0.17.5 - 2022-02-16
...
### 0.17.4 - 2022-02-04

Expected:

## 0.17.5 - 2022-02-16
...
## 0.17.4 - 2022-02-04
```</div>