Bump io.openliberty.tools:liberty-maven-plugin in /start

Bumps [io.openliberty.tools:liberty-maven-plugin](https://github.com/OpenLiberty/ci.maven) from 3.11.5 to 3.12.0.
- [Release notes](https://github.com/OpenLiberty/ci.maven/releases)
- [Commits](OpenLiberty/ci.maven@liberty-maven-3.11.5...liberty-maven-3.12.0)

---
updated-dependencies:
- dependency-name: io.openliberty.tools:liberty-maven-plugin
  dependency-version: 3.12.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

start/pom.xml

@@ -84,7 +84,7 @@ xsi:schemaLocation=
             <plugin>
                 <groupId>io.openliberty.tools</groupId>
                 <artifactId>liberty-maven-plugin</artifactId>
-                <version>3.11.5</version>
+                <version>3.12.0</version>
             </plugin>
 
             <!-- Plugin to run functional tests -->