fix: correct config of maven assembly plugin

use mvn package to generate single JAR.

fixes cloudspannerecosystem#109

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "1.22.0"
+}

README.md

@@ -181,7 +181,7 @@ mvn generate-resources compile exec:java \
 ### Generate JAR with dependencies and run from JAR file
 
 ```sh
-mvn clean generate-resources compile assembly:assembly
+mvn clean generate-resources compile package
 
 java -jar target/spanner-ddl-diff-*-jar-with-dependencies.jar \
       --allowRecreateIndexes \

pom.xml

@@ -18,7 +18,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud.solutions</groupId>
   <artifactId>spanner-ddl-diff</artifactId>
-  <version>1.0</version>
+  <version>1.22.0</version>
   <name>spanner-ddl-diff</name>
   <description>Spanner DDL parser and differ</description>
   <properties>
@@ -40,6 +40,7 @@
     <auto-value.version>1.10.4</auto-value.version>
     <error-prone.version>2.27.1</error-prone.version>
     <maven-checkstyle-plugin.version>3.3.1</maven-checkstyle-plugin.version>
+    <maven-assembly-plugin.version>3.7.1</maven-assembly-plugin.version>
   </properties>
   <dependencies>
     <dependency>
@@ -106,6 +107,10 @@
           <artifactId>maven-failsafe-plugin</artifactId>
           <version>${maven-surefire-plugin.version}</version>
         </plugin>
+        <plugin>
+          <artifactId>maven-assembly-plugin</artifactId>
+          <version>${maven-assembly-plugin.version}</version>
+        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>
@@ -246,6 +251,7 @@
       </plugin>
       <plugin>
         <artifactId>maven-assembly-plugin</artifactId>
+        <version>${maven-assembly-plugin.version}</version>
         <configuration>
           <archive>
             <manifest>
@@ -256,6 +262,15 @@
             <descriptorRef>jar-with-dependencies</descriptorRef>
           </descriptorRefs>
         </configuration>
+                <executions>
+          <execution>
+            <id>make-assembly</id> <!-- this is used for inheritance merges -->
+            <phase>package</phase> <!-- bind to the packaging phase -->
+            <goals>
+              <goal>single</goal>
+            </goals>
+          </execution>
+        </executions>
       </plugin>
       <plugin>
         <groupId>com.diffplug.spotless</groupId>

release-please-config.json

@@ -0,0 +1,14 @@
+{
+  "packages": {
+    ".": {
+      "changelog-path": "CHANGELOG.md",
+      "release-type": "maven",
+      "bump-minor-pre-major": false,
+      "bump-patch-for-minor-pre-major": false,
+      "draft": false,
+      "prerelease": false,
+      "include-component-in-tag": false
+    }
+  },
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"
+}