Release 3.9.1

Changes

• Update XAMLMarkupExtensions to 2.1.2 @konne (#326)
• preRelease @konne (#325)
• Bump System.Drawing.Common from 5.0.2 to 6.0.0 in /src @dependabot (#320)
• Bump System.Management from 5.0.0 to 6.0.0 in /src @dependabot (#319)
• Bump Microsoft.SourceLink.GitHub from 1.1.0 to 1.1.1 in /src @dependabot (#324)
• prep Release @konne (#323)
• Bump Microsoft.SourceLink.GitHub from 1.0.0 to 1.1.0 in /src @dependabot (#322)
• Update README.md @drummendejef (#321)