Added apt package cache to CI

.gitlab-ci.yml

-build-container:
+cache:
+  paths:
+    - apt-cache/
+
+build:
   stage: build
   image: wiktorguz/qt6
-  script:
-    - apt update && apt upgrade -y
-    - apt install -y software-properties-common
+  before_script:
+    - apt update && apt upgrade -o dir::cache::archives="apt-cache" -y
+    - apt install -o dir::cache::archives="apt-cache" -y software-properties-common
     - add-apt-repository -y ppa:ubuntu-toolchain-r/test && apt update
-    - apt install -y libswscale-dev libswresample-dev libpostproc-dev libavutil-dev libavresample-dev libavformat-dev libavfilter-extra libavfilter-dev libavdevice-dev libavcodec-extra libavcodec-dev ffmpeg git cmake libvulkan-dev gcc-10 gcc-10-base gcc-10-doc g++-10 libopenal-dev
+    - apt install -o dir::cache::archives="apt-cache" -y libswscale-dev libswresample-dev libpostproc-dev libavutil-dev libavresample-dev libavformat-dev libavfilter-extra libavfilter-dev libavdevice-dev libavcodec-extra libavcodec-dev ffmpeg git cmake libvulkan-dev gcc-10 gcc-10-base gcc-10-doc g++-10 libopenal-dev
+  script:
     - mkdir build && cd build
     - cmake -DCMAKE_C_COMPILER=/usr/bin/gcc-10 -DCMAKE_CXX_COMPILER=/usr/bin/g++-10 -DCMAKE_BUILD_TYPE=Debug .. && cmake --build . -j4
+  artifacts:
+    paths:
+      - build/AVQt/libAVQt.so
+      - AVQt/
+    expire_in: 1 week