Release v2.3.0: add multi-sheet support into xlsx data processor

What's Changed

• GH-197: if xlsx sheets have the same structure, it's now possible to retrieve data from multiple sources with additionalSources builder method. On the other hand, you can still use repeatable @Sheets annotation for static sheet names. By @sskorol in GH-198.
• Periodic dependencies' updates by @sskorol via @dependabot.