WIP: GitHub: try to fix upload in GitHub actions

GitHub deprecated [1] artifact up- and download actions and dependabot
tries to be smart[2], but doesn't read GitHubs own migration guide, which
states clearly that you have to update both up- and download to v4...

[1] https://github.blog/changelog/2024-02-13-deprecation-notice-v1-and-v2-of-the-artifact-actions/
[2] caadeb6

.github/workflows/build.yml

@@ -11,7 +11,7 @@ jobs:
         run: meson build && ninja -C build
       - name: compile example
         run: meson example/build example && ninja -C example/build
-      - uses: actions/upload-artifact@v2
+      - uses: actions/upload-artifact@v4
         with:
           name: ubuntu-meson
           path: |
@@ -25,7 +25,7 @@ jobs:
       - uses: actions/checkout@v2
       - name: compile library
         run: cmake -S . -B build && cmake --build build
-      - uses: actions/upload-artifact@v2
+      - uses: actions/upload-artifact@v4
         with:
           name: ubuntu-cmake
           path: |
@@ -36,12 +36,12 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Download artifact ubuntu-meson
-      uses: actions/download-artifact@v3
+      uses: actions/download-artifact@v4
       with:
         name: ubuntu-meson
         path: ./build-ubuntu-meson
     - name: Download artifact ubuntu-cmake
-      uses: actions/download-artifact@v3
+      uses: actions/download-artifact@v4
       with:
         name: ubuntu-cmake
         path: ./build-ubuntu-cmake