[Build] Attempt to sign docs to allow release (take2)

spring-pulsar-docs/build.gradle

@@ -190,3 +190,17 @@ publishing {
 artifactoryPublish {
 	publications(publishing.publications.mavenJava)
 }
+
+signing {
+	required { project.hasProperty("signing.keyId") || project.hasProperty("signingKey") && gradle.taskGraph.hasTask("publishArtifacts") }
+	def signingKeyId = (String) project.findProperty("signing.keyId");
+	def signingKey = (String) project.findProperty("signingKey");
+	def signingPassword = (String) project.findProperty("signingPassword");
+	if (signingKeyId != null) {
+		useInMemoryPgpKeys(signingKeyId, signingKey, signingPassword);
+	}
+	else {
+		useInMemoryPgpKeys(signingKey, signingPassword);
+	}
+	sign publishing.publications.mavenJava
+}

spring-pulsar-docs/src/main/java/org/springframework/pulsar/docs/Placeholder.java

@@ -1,21 +0,0 @@
-/*
- * Copyright 2022 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.pulsar.docs;
-
-public class Placeholder {
-
-}