"Publish plugin" workflow from the github plugin template fails

The workflow to publish my plugin always fails, see here.

The console output on GitHub is:

> Task :compileKotlin NO-SOURCE 
> Task :compileJava NO-SOURCE 
> Task :setupDependencies
> Task :patchPluginXml FAILED 

FAILURE: Build failed with an exception.
 
* What went wrong: 
Execution failed for task ':patchPluginXml'. 
> Error while evaluating property 'changeNotes' of task ':patchPluginXml' 
 > Failed to calculate the value of task ':patchPluginXml' property 'changeNotes'. 
 > org.jetbrains.changelog.exceptions.HeaderParseException: Header '[0.3]' does not contain version number. 

* Try: 
> Run with --stacktrace option to get the stack trace. 
> Run with --info or --debug option to get more log output. 
> Run with --scan to get full insights. 

* Get more help at https://help.gradle.org

BUILD FAILED in 1s 
2 actionable tasks: 2 executed 
Error: Process completed with exit code 1.

My changelog looks like this:

# Changelog

## [Unreleased]

### Added

- ...

## [0.2.1]

...

I regularly update my repo to the latest update of the template manually, so maybe I missed some files. However, I already checked that and everything seems ok.