CI: Try to enable backports

.gitlab-ci.yml

@@ -15,9 +15,10 @@
             - $CI_COMMIT_TITLE        =~ /.*\[NO-BUILD\].*/
     before_script:
         - lsb_release -a
+        - echo "deb http://deb.debian.org/debian bullseye-backports main" >> /etc/apt/sources.list
         - apt update && apt -y install make libmpv-dev cmake clang clang-format gcc g++ xxd mkvtoolnix
-            libcurl4-openssl-dev libsqlite3-dev manpages man-db libfontconfig-dev 
-            qt6-base qt6-declarative qt6-multimedia qt6-multimedia-ffmpeg
+            libcurl4-openssl-dev libsqlite3-dev manpages man-db libfontconfig-dev
+            qt6-base-dev qt6-declarative-dev qt6-multimedia-dev qt6-multimedia-ffmpeg-dev
         - curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup.sh
         - chmod +x ./rustup.sh
         - ./rustup.sh -y --default-toolchain beta