ci: Add workflow to confirm build completes

.github/workflows/build.yml

@@ -0,0 +1,24 @@
+name: Check build
+
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    name: Check build
+    strategy:
+      fail-fast: false
+      matrix:
+        luaVersion: [ "5.4", "5.3", "5.2", "5.1", "luajit", "luajit-openresty"]
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Setup ‘lua’
+        uses: leafo/gh-actions-lua@v9
+        with:
+          luaVersion: ${{ matrix.luaVersion }}
+      - name: Setup ‘luarocks’
+        uses: leafo/gh-actions-luarocks@v4
+      - name: Make with Luarocks
+        run: |
+          luarocks make --pack-binary-rock -- luasocket-scm-3.rockspec