ci(release): merge 4 jobs into 2

No need to do this in as many jobs. Splitting all the github stuff from
docker stuff into two jobs is enough. This still allows to conditionally
enable docker jobs in contributors repos, depending on whether the
relevant docker credentials are provided - but avoids using too many
concurrent runners.

.github/workflows/release.yaml

@@ -19,8 +19,10 @@ jobs:
       CACHIX_AUTH_TOKEN: ${{ secrets.CACHIX_AUTH_TOKEN }}
 
 
-  prepare:
+  github:
-    name: Prepare
+    name: GitHub
+    permissions:
+      contents: write
     runs-on: ubuntu-slim
     needs:
       - build
@@ -47,23 +49,7 @@ jobs:
 
           echo "Relevant extract from CHANGELOG.md:"
           cat CHANGES.md
-      - name: Save CHANGES.md as artifact
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
-        with:
-          name: release-changes
-          path: CHANGES.md
-          if-no-files-found: error
 
-
-  github:
-    name: GitHub
-    permissions:
-      contents: write
-    runs-on: ubuntu-slim
-    needs:
-      - prepare
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Download all artifacts
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
@@ -115,14 +101,14 @@ jobs:
             gh release edit devel \
               -t devel \
               --verify-tag \
-              -F artifacts/release-changes/CHANGES.md \
+              -F CHANGES.md \
               --prerelease
             gh release upload --clobber devel release-bundle/*
           else
             gh release create "${GITHUB_REF_NAME}" \
               -t "${GITHUB_REF_NAME}" \
               --verify-tag \
-              -F artifacts/release-changes/CHANGES.md \
+              -F CHANGES.md \
               release-bundle/*
           fi
 
@@ -131,7 +117,7 @@ jobs:
     name: Docker Hub
     runs-on: ubuntu-24.04-arm
     needs:
-      - prepare
+      - github
     if: |
       vars.DOCKER_REPO && vars.DOCKER_USER
     env:
@@ -177,16 +163,8 @@ jobs:
             echo "Skipping push to 'latest' tag for pre-release..."
           fi
 
-
-  docker-description:
-    name: Docker Hub Description
-    runs-on: ubuntu-slim
-    if: |
-      vars.DOCKER_REPO && vars.DOCKER_USER &&
-      github.ref == 'refs/tags/devel'
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - uses: peter-evans/dockerhub-description@1b9a80c056b620d92cedb9d9b5a223409c68ddfa # v5.0.0
+        name: Docker Hub Description
         with:
           username: ${{ vars.DOCKER_USER }}
           password: ${{ secrets.DOCKER_PASS }}