Add condition to reset content-type only if it isd not already set

Polish some of the POMs to address missing dependencies
Temporary disconnect gcp background sample until errors are fixed

spring-cloud-function-samples/function-sample-gcp-background/pom.xml

@@ -31,7 +31,6 @@
 		<plugins>
 			<plugin>
 				<artifactId>maven-deploy-plugin</artifactId>
-				<version>2.8.2</version>
 				<configuration>
 					<skip>true</skip>
 				</configuration>
@@ -62,4 +61,33 @@
 			</plugin>
 		</plugins>
 	</build>
+	<repositories>
+		<repository>
+			<id>spring-snapshots</id>
+			<name>Spring Snapshots</name>
+			<url>https://repo.spring.io/libs-snapshot-local</url>
+			<snapshots>
+				<enabled>true</enabled>
+			</snapshots>
+			<releases>
+				<enabled>false</enabled>
+			</releases>
+		</repository>
+		<repository>
+			<id>spring-milestones</id>
+			<name>Spring Milestones</name>
+			<url>https://repo.spring.io/libs-milestone-local</url>
+			<snapshots>
+				<enabled>false</enabled>
+			</snapshots>
+		</repository>
+		<repository>
+			<id>spring-releases</id>
+			<name>Spring Releases</name>
+			<url>https://repo.spring.io/release</url>
+			<snapshots>
+				<enabled>false</enabled>
+			</snapshots>
+		</repository>
+	</repositories>
 </project>