ci(flatpak): build on KDE 6.10

Author: Nerixyz

.github/workflows/build.yml

@@ -170,7 +170,7 @@ jobs:
   build-flatpak:
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/flathub-infra/flatpak-github-actions:kde-6.8
+      image: ghcr.io/flathub-infra/flatpak-github-actions:kde-6.10
       options: --privileged
     steps:
       - uses: actions/checkout@v6