[Build] Use the only GPG-key by default when signing Maven artifacts

This avoids the need to specify and maintain the id of the key to use.
Because the keyring only includes one key, there is no need to specify
that one explicitly as it's then the first one and therefore chosen by
default.

JenkinsJobs/Releng/publishToMaven.jenkinsfile

@@ -94,17 +94,6 @@ pipeline {
 										echo -e "5\ny\n" |  gpg --batch --command-fd 0 --expert --edit-key ${fpr} trust
 									done
 
-									if [ ${PROJECT} == platform ]; then
-										GPG_KEY_ID=CC641282
-									elif [ ${PROJECT} == pde ]; then
-										GPG_KEY_ID=86085154
-									elif [ ${PROJECT} == jdt ]; then
-										GPG_KEY_ID=B414F87E
-									else
-										echo "Unexpected project: '$PROJECT'"
-										exit 1
-									fi
-
 									# Copy configuration pom into clean directory to stop maven from finding the .mvn folder of this git-repository
 									cp "${WORKSPACE}/git-repo/eclipse-platform-parent/pom.xml" eclipse-parent-pom.xml
 
@@ -160,7 +149,7 @@ pipeline {
 										set -x
 
 										mvn -f eclipse-parent-pom.xml -s ${SETTINGS} \\
-											gpg:sign-and-deploy-file -Dgpg.key.id=${GPG_KEY_ID} \\
+											gpg:sign-and-deploy-file -DretryFailedDeploymentCount=5 \\
 											-Durl=${URL} -DrepositoryId=${REPO_ID} \\
 											-DpomFile=${pomFile} -Dfile=${file} \\
 											${SOURCES_ARG} ${JAVADOC_ARG}

eclipse-platform-parent/pom.xml

@@ -714,13 +714,6 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-gpg-plugin</artifactId>
           <version>3.2.7</version>
-          <configuration>
-            <gpgArguments>
-              <arg>--default-key</arg>
-              <arg>${gpg.key.id}</arg>
-            </gpgArguments>
-            <retryFailedDeploymentCount>5</retryFailedDeploymentCount>
-          </configuration>
         </plugin>
       </plugins>
     </pluginManagement>