Bump vaadin.version from 24.8.7 to 24.8.8 (#14)

Bumps `vaadin.version` from 24.8.7 to 24.8.8.

Updates `com.vaadin:vaadin-bom` from 24.8.7 to 24.8.8

Updates `com.vaadin:vaadin-maven-plugin` from 24.8.7 to 24.8.8
- [Release notes](https://github.com/vaadin/platform/releases)
- [Commits](vaadin/platform@24.8.7...24.8.8)

---
updated-dependencies:
- dependency-name: com.vaadin:vaadin-bom
  dependency-version: 24.8.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: com.vaadin:vaadin-maven-plugin
  dependency-version: 24.8.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]

ssh-key-signer-server/pom.xml

@@ -13,7 +13,7 @@
 
     <properties>
         <java.version>21</java.version>
-        <vaadin.version>24.8.7</vaadin.version>
+        <vaadin.version>24.8.8</vaadin.version>
         <ssh-signer-common-lib.version>0.0.3</ssh-signer-common-lib.version>
     </properties>