Make version parameter optional (#13)

Author: nakamura-to

.github/workflows/pre-release.yml

@@ -5,7 +5,7 @@ on:
     inputs:
       version:
         description: 'Release version'
-        required: true
+        required: false
 
 jobs:
   pre-release:
@@ -36,12 +36,30 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-gradle-
 
-      - name: Pre Release ${{ github.event.inputs.version }}
+      - uses: actions/github-script@v3
+        id: release-version
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          result-encoding: string
+          script: |
+            const version = core.getInput("version");
+            console.log("version=" + version)
+            if (version) {
+              return version
+            }
+            const list = await github.repos.listReleases({
+              owner: "domaframework",
+              repo: "sandbox",
+            });
+            console.log(list)
+            return list.data[0].name
+
+      - name: Pre Release ${{ steps.release-version.outputs.result }}
         run: |
           java -version
           git config --global user.name "github-actions[bot]"
           git config --global user.email "41898282+github-actions[bot]@users.noreply.github.com"
-          ./gradlew release -Prelease.releaseVersion=${{ github.event.inputs.version }}
+          ./gradlew release -Prelease.releaseVersion=${{ steps.release-version.outputs.result }}
 
       - name: Upload reports
         if: failure()