chore: Bump framework.version from 8.27.7 to 8.28.1

Bumps `framework.version` from 8.27.7 to 8.28.1.

Updates `com.vaadin:vaadin-client` from 8.27.7 to 8.28.1
- [Release notes](https://github.com/vaadin/framework/releases)
- [Changelog](https://github.com/vaadin/framework/blob/master/CHANGELOG-VAADIN8.md)
- [Commits](vaadin/framework@8.27.7...8.28.1)

Updates `com.vaadin:vaadin-client-compiler` from 8.27.7 to 8.28.1
- [Release notes](https://github.com/vaadin/framework/releases)
- [Changelog](https://github.com/vaadin/framework/blob/master/CHANGELOG-VAADIN8.md)
- [Commits](vaadin/framework@8.27.7...8.28.1)

Updates `com.vaadin:vaadin-server` from 8.27.7 to 8.28.1
- [Release notes](https://github.com/vaadin/framework/releases)
- [Changelog](https://github.com/vaadin/framework/blob/master/CHANGELOG-VAADIN8.md)
- [Commits](vaadin/framework@8.27.7...8.28.1)

---
updated-dependencies:
- dependency-name: com.vaadin:vaadin-client
  dependency-version: 8.28.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: com.vaadin:vaadin-client-compiler
  dependency-version: 8.28.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: com.vaadin:vaadin-server
  dependency-version: 8.28.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

vaadin-spreadsheet-flow-parent/vaadin-spreadsheet-flow-client/pom.xml

@@ -38,7 +38,7 @@
         <!-- we dont put this dependencies in parent poms because they are only
          used in this module just for the compilation Java to JS -->
         <gwt.version>2.9.0</gwt.version>
-        <framework.version>8.27.7</framework.version>
+        <framework.version>8.28.1</framework.version>
     </properties>
 
     <dependencyManagement>