Add Ubuntu 26.04 to deb package build matrix

Author: moetiker

.github/workflows/build_deb_packages.yaml

@@ -29,6 +29,8 @@ jobs:
             version: 22.04
           - distribution: ubuntu
             version: 24.04
+          - distribution: ubuntu
+            version: 26.04
 
     runs-on: ubuntu-latest
     name: Build package for ${{ matrix.distribution }} ${{ matrix.version }}