Add github workflows

.github/workflows/gem-push.yml

@@ -0,0 +1,27 @@
+name: Ruby Gem
+
+on:
+  workflow_dispatch:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  build:
+    name: Build + Publish
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Ruby 2.7
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.7
+      - name: push gem
+        uses: trocco-io/push-gem-to-gpr-action@v2
+        with:
+          language: java
+          gem-path: "./build/gems/*.gem"
+          github-token: "${{ secrets.GITHUB_TOKEN }}"

build.gradle

@@ -4,14 +4,22 @@ plugins {
     id "signing"
     id "org.embulk.embulk-plugins" version "0.5.5"
     id "checkstyle"
+    id "com.palantir.git-version" version "3.1.0"
 }
 
 repositories {
     mavenCentral()
 }
 
 group = "org.embulk"
-version = "1.7.1-SNAPSHOT"
+version = {
+    def vd = versionDetails()
+    if (vd.commitDistance == 0 && vd.lastTag ==~ /^[0-9]+\.[0-9]+\.[0-9]+([.-][.a-zA-Z0-9-]+)?/) {
+        vd.lastTag
+    } else {
+        "0.0.0.${vd.gitHash}"
+    }
+}()
 description = "Stores files on S3."
 
 sourceCompatibility = JavaVersion.VERSION_1_8