Add manual snapshot workflow

Created a new GitHub Actions workflow for manually triggering snapshots to the SNAPSHOT repository. Updated the project version in gradle.properties to 0.0.9-SNAPSHOT.

.github/workflows/snapshot_manual.yml

@@ -0,0 +1,27 @@
+name: Manual Snapshot Push to SNAPSHOT repo
+
+on:
+  workflow_dispatch:
+
+jobs:
+  commit-build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          submodules: 'true'
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+          distribution: 'temurin'
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+      - name: Build with Gradle
+        run: ./gradlew clean build -PskipSigning=true --stacktrace
+      - name: Publish package to SNAPSHOT repository
+        run: ./gradlew publish -PskipSigning=true --warn --stacktrace
+        env:
+          MAVEN_USERNAME: ${{ secrets.OSSRH_USERNAME }}
+          MAVEN_PASSWORD: ${{ secrets.OSSRH_TOKEN }}

gradle.properties

@@ -1,4 +1,4 @@
 group = com.bloxbean.cardano
 artifactId = aiken-java-binding
-version = 0.0.9-rc2
+version = 0.0.9-SNAPSHOT