PySDM v3.0.0-pre.28

What's Changed

• Bump pypartmc from 1.7.2 to 2.0.6 by @dependabot[bot] in #1839
• Add isotopic composition from Rayleigh model to Graf_2019 by @AgnieszkaZaba in #1841
• Add GitHub Actions to Dependabot configuration (thanks @gucio321) by @slayoo in #1845
• Bump pympdata from 1.7.0 to 1.7.1 in /examples by @dependabot[bot] in #1844

Full Changelog: v3.0.0-pre.27...v3.0.0-pre.28