Add Java CI with Maven workflow to Maven project with my own dependencies

I have a GitHub repo with this three Maven projects inside:

• Client
• Server
• Engine

I want to apply the Java CI with Maven workflow, the configuration is this one:

# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-maven
# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.
name: Java CI with Maven
on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up JDK 17
        uses: actions/setup-java@v3
        with:
          java-version: '17'
          distribution: 'temurin'
          cache: maven
      - name: Build with Maven -> Client
        run: mvn -B package --file client/pom.xml
      - name: Build with Maven -> Engine
        run: mvn -B package --file engine/pom.xml
      - name: Build with Maven -> Server
        run: mvn -B package --file server/pom.xml
      # Optional: Uploads the full dependency graph to GitHub to improve the quality of Dependabot alerts this repository can receive
      - name: Update dependency graph
        uses: advanced-security/maven-dependency-submission-action@571e99aab1055c2e71a1e2309b9691de18d6b7d6

The problem comes with the Server pom, looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		 xmlns="http://maven.apache.org/POM/4.0.0"
		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>org.victorpiles.escacs</groupId>
	<artifactId>server</artifactId>
	<version>1.0-SNAPSHOT</version>

	<properties>
		<maven.compiler.source>17</maven.compiler.source>
		<maven.compiler.target>17</maven.compiler.target>
	</properties>

	<dependencies>
		<!-- Engine -->
		<dependency>
			<groupId>org.victorpiles.escacs</groupId>
			<artifactId>engine</artifactId>
			<version>1.0-SNAPSHOT</version>
		</dependency>
		<!-- Lombok -->
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.26</version>
			<scope>compile</scope>
		</dependency>
	</dependencies>
</project>

So the Server has the Engine as a dependency and GitHub can't resolve this dependency.

The pom of the Engine is the following:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		 xmlns="http://maven.apache.org/POM/4.0.0"
		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>org.victorpiles.escacs</groupId>
	<artifactId>engine</artifactId>
	<version>1.0-SNAPSHOT</version>

	<properties>
		<maven.compiler.source>17</maven.compiler.source>
		<maven.compiler.target>17</maven.compiler.target>
	</properties>

	<dependencies>
		<!-- Lombok -->
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.26</version>
			<scope>compile</scope>
		</dependency>
	</dependencies>
</project>

The following error is thrown when running the Workflow:

[INFO] Scanning for projects...
[INFO] 
[INFO] -------------------< org.victorpiles.escacs:server >--------------------
[INFO] Building server 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
Warning:  The POM for org.victorpiles.escacs:engine:jar:1.0-SNAPSHOT is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  0.282 s
[INFO] Finished at: 2023-03-20T15:12:47Z
[INFO] ------------------------------------------------------------------------
Error:  Failed to execute goal on project server: Could not resolve dependencies for project org.victorpiles.escacs:server:jar:1.0-SNAPSHOT: Could not find artifact org.victorpiles.escacs:engine:jar:1.0-SNAPSHOT -> [Help 1]
Error:  
Error:  To see the full stack trace of the errors, re-run Maven with the -e switch.
Error:  Re-run Maven using the -X switch to enable full debug logging.
Error:  
Error:  For more information about the errors and possible solutions, please read the following articles:
Error:  [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
Error: Process completed with exit code 1.

Your project should have been a multi-module project.

Put a pom.xml into the root directory of the project which lists the other directories as <modules>. Then you build the root POM and everything will be build automatically, with resolved dependencies.