Add starter dependency for Secret Manager (spring-attic#2184)

Adds the starter dependency for Secret Manager. Contributes to spring-attic#2176.

Author: dzou

spring-cloud-gcp-starters/pom.xml

@@ -38,5 +38,6 @@
 		<module>spring-cloud-gcp-starter-data-firestore</module>
 		<module>spring-cloud-gcp-starter-bigquery</module>
 		<module>spring-cloud-gcp-starter-security-firebase</module>
-    </modules>
+		<module>spring-cloud-gcp-starter-secretmanager</module>
+	</modules>
 </project>

spring-cloud-gcp-starters/spring-cloud-gcp-starter-secretmanager/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<parent>
+		<groupId>org.springframework.cloud</groupId>
+		<artifactId>spring-cloud-gcp-starters</artifactId>
+		<version>1.3.0.BUILD-SNAPSHOT</version>
+	</parent>
+	<modelVersion>4.0.0</modelVersion>
+
+	<name>Spring Cloud GCP Pub/Sub Starter</name>
+	<artifactId>spring-cloud-gcp-starter-secretmanager</artifactId>
+	<description>Starter for GCP Secret Manager</description>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-gcp-starter</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-context</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>com.google.cloud</groupId>
+			<artifactId>google-cloud-secretmanager</artifactId>
+		</dependency>
+	</dependencies>
+</project>