CI: replace upload_files_to_github_release.py

.github/workflows/release.yml

@@ -195,6 +195,10 @@ jobs:
         run: |
           cd ${GITHUB_WORKSPACE}/sage-windows
           bash release_gap.sh
+          NAME=Output/gap-${{ env.GAP_BUILD_VERSION }}-x86_64.exe
+          printf "%s" "$(sha256sum $NAME | cut -c1-64)" >$NAME.sha256
+          ls -l $NAME.sha256  # FIXME/HACK: remove this line again
+
         env:
           ARCH: x86_64
           SAGE_BUILD_DOC_CMD: '"true"'
@@ -210,18 +214,13 @@ jobs:
           path: sage-windows/Output/gap-${{ env.GAP_BUILD_VERSION }}-x86_64.exe
           retention-days: 1
 
-      # To reduce code, we could use an Action from the GitHub Marketplace to
-      # upload to the release, rather than use our own script.  We would still
-      # have to create the .sha256 file, and upload it here too.
-      - name: "Upload the installer to the GitHub release"
+      - name: "Upload the installer to tag"
+        uses: softprops/action-gh-release@v1
         if: ${{ startsWith(github.ref, 'refs/tags/v') }}
-        run: |
-          python -u \
-            ./releases/upload_files_to_github_release.py \
-            v${GAP_BUILD_VERSION} \
-            sage-windows/Output/gap-${GAP_BUILD_VERSION}-x86_64.exe
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          files: |
+            sage-windows/Output/gap-${{ env.GAP_BUILD_VERSION }}-x86_64.exe
+            sage-windows/Output/gap-${{ env.GAP_BUILD_VERSION }}-x86_64.exe.sha256
 
   # The following job is duplicated in CI.yml - keep the two in sync.
   # (except for their different 'needs' components).