Unified release workflow for shaded and thin JARs (#1073)

## Summary
This PR implements a unified release workflow that publishes both the
shaded uber JAR and thin JAR to Maven Central in a single GitHub Actions
workflow.

## Changes
1. **Added `build-helper-maven-plugin`** to `pom.xml`:
- Attaches the unshaded JAR with `-thin` classifier before the shade
plugin runs
   - Preserves the original JAR as `databricks-jdbc-${VERSION}-thin.jar`

2. **Updated `.github/workflows/release.yml`**:
   - Added GPG configuration for signing
   - Kept existing step to deploy shaded JAR (main artifact)
- Added new step to deploy thin JAR as separate artifact with custom POM

3. **Removed `.github/workflows/release-thin.yml`**:
- No longer needed - both JARs now published in single unified workflow

## Published Artifacts
- **Shaded JAR**: `com.databricks:databricks-jdbc:3.0.1` (37MB, includes
all dependencies)
- **Thin JAR**: `com.databricks:databricks-jdbc-thin:3.0.1` (2.4MB,
driver classes only)

## Testing
```bash
mvn clean && mvn -B -DskipTests package
# Verified both JARs created successfully:
# - target/databricks-jdbc-3.0.1.jar (37MB shaded)
# - target/databricks-jdbc-3.0.1-thin.jar (2.4MB thin)
```

## Backward Compatibility
✅ Existing users are unaffected - the main artifact remains the shaded
uber JAR

---
NO_CHANGELOG=true

---------

Signed-off-by: Gopal Lal <gopal.lal@databricks.com>

Author: gopalldb

.github/workflows/release-thin.yml

@@ -27,9 +27,15 @@ jobs:
           gpg-private-key: ${{ secrets.GPG_PRIVATE_KEY }}
           gpg-passphrase: GPG_PASSPHRASE
 
-      - name: Publish to the Maven Central Repository
+      - name: Configure GPG
         run: |
-          # Deploy main artifacts (uber JAR, sources, javadoc)
+          echo "allow-loopback-pinentry" >> ~/.gnupg/gpg-agent.conf
+          echo "pinentry-mode loopback" >> ~/.gnupg/gpg.conf
+          gpg-connect-agent reloadagent /bye
+
+      - name: Publish shaded JAR to Maven Central
+        run: |
+          # Deploy main artifacts (shaded uber JAR, sources, javadoc)
           mvn -Prelease --batch-mode deploy \
             -Dnvd.api.key=${{ secrets.NVD_API_KEY }} \
             -Dossindex.username=${{ secrets.OSSINDEX_USERNAME }} \
@@ -39,8 +45,26 @@ jobs:
           MAVEN_CENTRAL_USERNAME: ${{ secrets.MAVEN_CENTRAL_USERNAME }}
           MAVEN_CENTRAL_PASSWORD: ${{ secrets.MAVEN_CENTRAL_PASSWORD }}
 
+      - name: Publish thin JAR as separate artifact to Maven Central
+        run: |
+          VERSION=$(grep -m1 '<version>' pom.xml | sed 's/.*<version>\(.*\)<\/version>.*/\1/')
+          mvn -Prelease gpg:sign-and-deploy-file \
+            -Dfile="target/databricks-jdbc-${VERSION}-thin.jar" \
+            -DpomFile=thin_public_pom.xml \
+            -DrepositoryId=central \
+            -Durl=https://oss.sonatype.org/service/local/staging/deploy/maven2/ \
+            -DgroupId=com.databricks \
+            -DartifactId=databricks-jdbc-thin \
+            -Dversion="${VERSION}" \
+            -Dpackaging=jar \
+            -Dgpg.passphrase="${GPG_PASSPHRASE}"
+        env:
+          GPG_PASSPHRASE: ${{ secrets.GPG_PASSPHRASE }}
+          MAVEN_CENTRAL_USERNAME: ${{ secrets.MAVEN_CENTRAL_USERNAME }}
+          MAVEN_CENTRAL_PASSWORD: ${{ secrets.MAVEN_CENTRAL_PASSWORD }}
+
       - name: Create GitHub release
         uses: softprops/action-gh-release@v1
         with:
           files: |
-            files: target/*.jar
+            target/*.jar

.github/workflows/release.yml

@@ -474,6 +474,30 @@
           </excludes>
         </configuration>
       </plugin>
+      <!-- Attach unshaded JAR before shade plugin runs -->
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <version>3.6.1</version>
+        <executions>
+          <execution>
+            <id>attach-thin-jar</id>
+            <phase>package</phase>
+            <goals>
+              <goal>attach-artifact</goal>
+            </goals>
+            <configuration>
+              <artifacts>
+                <artifact>
+                  <file>${project.build.directory}/${project.build.finalName}.jar</file>
+                  <type>jar</type>
+                  <classifier>thin</classifier>
+                </artifact>
+              </artifacts>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-shade-plugin</artifactId>