Update Qt version to 6.8.3 in CI (#6223)

Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Author: MiguelCompany

.github/workflows/reusable-ubuntu-ci.yml

@@ -622,8 +622,9 @@ jobs:
       - name: Install Qt
         uses: eProsima/eProsima-CI/external/install_qt@v0
         with:
-          version: '5.15.2'
-          dir: '${{ github.workspace }}/qt_installation/'
+          version: '6.8.3'
+          dir: '/opt/qt_installation/'
+          arch: 'linux_gcc_64'
           modules: 'qtcharts'
           setup-python: 'false'