Improve Changelog handling

[Kamik423]

A CHANGELOG.md should be included in the repository that then dynamically fills the notes in the Java code – potentially through a maven action.

EPUB-Checker/src/main/java/de/paginagmbh/epubchecker/PaginaEPUBChecker.java

Lines 27 to 34 in c885c50

	// +++++++++++++++++++++++++ DON'T FORGET TO UPDATE EVERYTIME ++++++++++++++++++ //
	public static final String PROGRAMVERSION = "2.0.10";
	public static final String VERSIONDATE = "2023-08-28";
	public static final String PROGRAMRELEASE = ""; // "" or "Beta"
	public static final String RELEASENOTES = "• Upgrade EPUBCheck to v5.1.0\n• Restored compatibility with newer Java versions\n• Internal improvements to the release and code signing process";
	// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ //