Switch to simpler p2-maven-plugin; housekeeping

.gitlab-ci.yml

 variables:
-  RELEASE_DIR: "public/release_target_211"
+  RELEASE_DIR: "public/p2repo"
 
 pages:
   stage: deploy
   tags: 
     - docker
-  image: maven:3.6.3-adoptopenjdk-15
+  image: maven:3.8.4-eclipse-temurin-17-alpine
   script:
     - mvn --version
     - mvn clean install   # build p2 repo

pom.xml

 <project xmlns="http://maven.apache.org/POM/4.0.0"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
-	<modelVersion>4.0.0</modelVersion>
-	<groupId>de.hft-stuttgart</groupId>
-	<artifactId>de.hft-stuttgart.indriya.parent</artifactId>
-	<version>1.0.0</version>
-	<packaging>pom</packaging>
-	<name>Indriya P2 site parent POM</name>
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
 
-	<properties>
-		<tycho-version>2.1.0</tycho-version>
-	</properties>
-
-	<build>
-		<plugins>
-			<plugin>
-				<groupId>org.eclipse.tycho</groupId>
-				<artifactId>tycho-maven-plugin</artifactId>
-				<version>${tycho-version}</version>
-				<configuration>
-					<source>15</source>
-					<target>15</target>
-					<encoding>UTF-8</encoding>
-				</configuration>
-				<extensions>true</extensions>
-			</plugin>
-
-			<plugin>
-				<groupId>org.eclipse.tycho</groupId>
-				<artifactId>target-platform-configuration</artifactId>
-				<version>${tycho-version}</version>
-				<configuration>
-					<pomDependencies>consider</pomDependencies>
-					<!-- executionEnvironment>JavaSE-15</executionEnvironment -->
-					<target>
-						<artifact>
-							<groupId>de.hft-stuttgart</groupId>
-							<artifactId>de.hft-stuttgart.indriya.target</artifactId>
-							<version>1.0.0</version>
-						</artifact>
-					</target>
-				</configuration>
-			</plugin>
-		</plugins>
-	</build>
-
-	<dependencies>
-		<dependency>
-			<groupId>tech.units</groupId>
-			<artifactId>indriya</artifactId>
-			<version>2.1.1</version>
-		</dependency>
-
-		<dependency>
-			<groupId>jakarta.inject</groupId>
-			<artifactId>jakarta.inject-api</artifactId>
-			<version>2.0.0</version>
-		</dependency>
-		<dependency>
-			<groupId>jakarta.annotation</groupId>
-			<artifactId>jakarta.annotation-api</artifactId>
-			<version>2.0.0</version>
-		</dependency>
-		<dependency>
-			<groupId>tech.uom.lib</groupId>
-			<artifactId>uom-lib-common</artifactId>
-			<version>2.1</version>
-		</dependency>
-	</dependencies>
-
-	<modules>
-		<module>de.hft-stuttgart.indriya.target</module>
-		<module>de.hft-stuttgart.indriya.feature</module>
-		<module>de.hft-stuttgart.indriya.p2site</module>
-	</modules>
+    <groupId>de.hft-stuttgart</groupId>
+    <artifactId>indriya-p2-site</artifactId>
+    <packaging>pom</packaging>
+    <version>1.2.0</version>
+    <name>Indriya P2 update site</name>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.reficio</groupId>
+                <artifactId>p2-maven-plugin</artifactId>
+                <version>2.0.0</version>
+                <executions>
+                    <execution>
+                        <id>default-cli</id>
+                        <configuration>
+                            <artifacts>
+                                <!-- specify your depencies here -->
+                                <!-- groupId:artifactId:version -->
+                                <artifact><id>tech.units:indriya:2.1.1</id></artifact>
+                                <artifact><id>tech.units:indriya:2.1.3</id></artifact>
+                            </artifacts>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
 </project>
\ No newline at end of file