mdbx-ci: engage github-actions to make release-assets.

Resolves https://github.com/erthink/libmdbx/issues/86

Change-Id: I87417c03bf0d657ece47a59aabbd3cb5bfaa81ec

.github/workflows/release-assets.yml

@@ -0,0 +1,54 @@
+# Based on the https://github.com/actions/upload-release-asset example
+
+on:
+  push:
+    # Sequence of patterns matched against refs/tags
+    tags:
+    - 'v*' # Push events to matching v*, i.e. v1.0, v20.15.10
+
+name: Upload Release Asset
+
+jobs:
+  build:
+    name: Upload Release Asset
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Build assets
+        run: |
+          make release-assets
+      - id: name
+        run: |
+          echo "::set-output name=tarball::$(ls *.tar.gz)"
+          echo "::set-output name=zip::$(ls *.zip)"
+      - name: Create Release
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: Release ${{ github.ref }}
+          draft: true
+          prerelease: true
+      - name: Upload tarball
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ${{ steps.name.outputs.tarball }}
+          asset_name: amalgamated.tar.gz
+          # asset_label: Amalgamated source tarball
+          asset_content_type: application/tar+gzip
+      - name: Upload zip
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ${{ steps.name.outputs.zip }}
+          asset_name: amalgamated.zip
+          # asset_label: Amalgamated source zip-archive
+          asset_content_type: application/zip