add alpine apisix-base workflow

Author: gxthrj

.github/workflows/package-apisix-base-apk.yml

@@ -0,0 +1,29 @@
+name: package apisix-base rpm for el7
+
+on:
+  push:
+    branches: [ openresty/* ]
+    tags:
+      - "v*"
+    paths-ignore:
+      - '*.md'
+  pull_request:
+    branches: [ master ]
+    paths-ignore:
+      - '*.md'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      BUILD_APISIX_BASE_VERSION: 1.19.3.2.0
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: install dependencies
+        run: |
+          sudo apt-get install -y make ruby ruby-dev rubygems build-essential
+
+      - name: build apisix-base apk
+        run: |
+          make package version=${BUILD_APISIX_BASE_VERSION} image_base=alpine image_tag=3.12 app=apisix-base type=apk