add workflow for pushing rockspec/rocks

Author: olegrok

.github/workflows/publish.yml

@@ -0,0 +1,27 @@
+name: Publish
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  publish:
+    if: startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: tarantool/setup-tarantool@v1
+        with:
+          tarantool-version: '2.7'
+
+      - run: echo "TAG=${GITHUB_REF##*/}" >> $GITHUB_ENV
+      - run: tarantoolctl rocks new_version --tag $TAG
+      - run: tarantoolctl rocks pack graphql-$TAG-1.rockspec
+
+      - uses: tarantool/rocks.tarantool.org/github-action@master
+        with:
+          auth: ${{ secrets.ROCKS_USERNAME }}:${{ secrets.ROCKS_PASSWORD }}
+          files: |
+            graphql-${{ env.TAG }}-1.rockspec
+            graphql-${{ env.TAG }}-1.src.rock