Build AppImage separately per OS

Different OS'es have different `GLIBC_X.XX` versions.

While installing extra libraries is of course maybe necessary,
it is next-to-impossible (AFAIU) to install/compliment a diffent
`GLIBC_X.XX` on non-flexible OSes such as Debian, Ubuntu, etc.

If AppImage is unable to hide those differences,
then we must diversify if we want to support a wider base.

Fixes: https://github.com/brndnmtthws/conky/issues/1142
Fixes: https://github.com/brndnmtthws/conky/issues/1717

... and probably others.

Signed-off-by: Stavros Ntentos <133706+stdedos@users.noreply.github.com>

.github/workflows/publish-appimage.yml

@@ -15,7 +15,12 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os:
+          - ubuntu-20.04
+          - ubuntu-22.04
     permissions:
       contents: write
       discussions: write
@@ -63,6 +68,9 @@ jobs:
             pip3 install --upgrade pyyaml
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Get git version
+        id: git-version
+        run: echo "GIT_VERSION=$(git describe --tags)" >> $GITHUB_ENV
       - name: Import GPG Deploy Key
         run: |
           echo "${{ secrets.GPG_DEPLOY_KEY }}" > appimage/secret.gpg
@@ -72,18 +80,32 @@ jobs:
       - name: Upload AppImage artifact
         uses: actions/upload-artifact@v4
         with:
-          name: conky-x86_64.AppImage
+          name: "conky-${{ matrix.os }}-${{ env.GIT_VERSION }}.AppImage"
           path: conky-x86_64.AppImage
+          if-no-files-found: error
       - name: Upload AppImage checksum artifact
         uses: actions/upload-artifact@v4
         with:
-          name: conky-x86_64.AppImage.sha256
+          name: "conky-${{ matrix.os }}-${{ env.GIT_VERSION }}.AppImage"
           path: conky-x86_64.AppImage.sha256
+          if-no-files-found: error
       - name: Upload man page artifact
         uses: actions/upload-artifact@v4
         with:
           name: conky.1.gz
           path: conky.1.gz
+
+  release:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          # conky.1.gz is created by all jobs!
+          merge-multiple: true
+          path: ${{ github.workspace }}/artifacts
+
       - name: Create Conky Release
         id: create_release
         uses: softprops/action-gh-release@v1
@@ -94,6 +116,5 @@ jobs:
           discussion_category_name: General
           generate_release_notes: true
           files: |
-            conky-x86_64.AppImage
+            conky-*.AppImage*
-            conky-x86_64.AppImage.sha256
             conky.1.gz