chore(main): release 2.1.6-SNAPSHOT (#701)

🤖 I have created a release *beep* *boop*
---


### Updating meta-information for bleeding-edge SNAPSHOT release.

---
This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

Author: release-please[bot]

pom.xml

@@ -4,7 +4,7 @@
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-dns</artifactId>
   <packaging>jar</packaging>
-  <version>2.1.5</version><!-- {x-version-update:google-cloud-dns:current} -->
+  <version>2.1.6-SNAPSHOT</version><!-- {x-version-update:google-cloud-dns:current} -->
   <name>Google Cloud DNS Parent</name>
   <url>https://github.com/googleapis/java-dns</url>
   <description>

samples/snapshot/pom.xml

@@ -28,7 +28,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-dns</artifactId>
-      <version>2.1.5</version>
+      <version>2.1.6-SNAPSHOT</version>
     </dependency>
     <!-- {x-version-update-end} -->
 

versions.txt

@@ -1,4 +1,4 @@
 # Format:
 # module:released-version:current-version
 
-google-cloud-dns:2.1.5:2.1.5
+google-cloud-dns:2.1.5:2.1.6-SNAPSHOT