ci: Remove "Package Build" GitHub Action

We would like to switch to exclusively using Packit for building and
testing pull requests, so we are retiring this GitHub Action workflow.
We will want to configure Packit to check that DNF5 compiles with both
GCC and clang, like the Package Build action did.

In order to fully disable the action, this commit must be applied on
each branch in the upstream DNF5 repository. Otherwise, the action might
be triggered by a pull request to some stale branch.

.github/workflows/package-build.yml

@@ -1,71 +0,0 @@
----
-name: Package Build
-on:
-  pull_request_target:
-  merge_group:
-    types: [checks_requested]
-
-jobs:
-  ccache-build:
-    name: CCache Build
-    runs-on: ubuntu-latest
-    container:
-      image: ghcr.io/rpm-software-management/dnf-ci-host
-    strategy:
-      fail-fast: false  # don't fail all matrix jobs if one of them fails
-      matrix:
-        compiler: [gcc, clang]  # gcc is the default
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-
-      - name: Configure CC CXX env variables
-        id: configure_compiler
-        run: |
-          if [[ "${{matrix.compiler}}" == "clang" ]]; then
-            echo "cxx=/usr/lib64/ccache/clang++" >> "$GITHUB_OUTPUT"
-            echo "cc=/usr/lib64/ccache/clang" >> "$GITHUB_OUTPUT"
-          else
-            echo "cxx=/usr/lib64/ccache/g++" >> "$GITHUB_OUTPUT"
-            echo "cc=/usr/lib64/ccache/gcc" >> "$GITHUB_OUTPUT"
-          fi
-
-      # make sure that for every build the GitHub Actions cache key is unique
-      - name: Prepare CCache timestamp
-        id: ccache_cache_timestamp
-        run:
-          echo "timestamp=$(date +%Y-%m-%d-%H:%M:%S)-UTC" >> "$GITHUB_OUTPUT"
-
-      - name: Cache CCache files
-        uses: actions/cache@v3
-        with:
-          path: ~/.cache/ccache
-          # cache is saved with this hierarchy
-          # dnf5-ccache-gcc-pr-main-111-2023-01-01-00:00:00-UTC
-          #          -clang-pr-main-111-2023-01-01-00:00:00-UTC
-          key: ${{ github.event.repository.name }}-ccache-${{ matrix.compiler }}-pr-${{ github.base_ref }}-${{ github.event.number }}-${{ steps.ccache_cache_timestamp.outputs.timestamp }}
-          # we want to match the latest cache prioritizing the same PR (e.g.
-          # 111), then the same branch (e.g. main), and, in all cases, we want
-          # to match the project-compiler (gcc,clang) match by date is not
-          # needed since caches are always matched by date.
-          #
-          # Example: dnf5-ccache-clang-pr-devel-111-2023-01-01-00:00:00-UTC will
-          # try to fetch cache from the same pr, 111 against devel. if no pr is
-          # found it will try to fetch any pr against devel branch.
-          restore-keys: |
-            ${{ github.event.repository.name }}-ccache-${{ matrix.compiler }}-pr-${{ github.base_ref }}-${{ github.event.number }}-
-
-      - name: Zero CCache statistics
-        run: ccache -z
-
-      - name: Configure DNF5 with CMake
-        run: CXX=${{ steps.configure_compiler.outputs.cxx }} CC=${{ steps.configure_compiler.outputs.cc }} cmake -S . -B build
-
-      - name: Build DNF5
-        id: ccache-build
-        run: cmake --build build
-
-      - name: Display CCache statistics
-        run: ccache -s