Use latest release for servlets.post

There are no code changes since 2.3.16, so let's keep it as
a released version.
diff --git a/pom.xml b/pom.xml
index 8da4c32..9c57365 100644
--- a/pom.xml
+++ b/pom.xml
@@ -85,7 +85,7 @@
         <dependency>
             <groupId>org.apache.sling</groupId>
             <artifactId>org.apache.sling.servlets.post</artifactId>
-            <version>2.3.17-SNAPSHOT</version>
+            <version>2.3.16</version>
             <scope>provided</scope>
         </dependency>
         <dependency>