chore(deps): update dependency com.google.cloud:google-cloud-document-ai to v2.1.6 (#659)

* chore(deps): update dependency com.google.cloud:google-cloud-document-ai to v2.1.6

* 🦉 Updates from OwlBot

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document-ai/snippets/pom.xml

@@ -41,7 +41,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-document-ai</artifactId>
-      <version>2.1.5</version>
+      <version>2.1.6</version>
     </dependency>
     <!-- [END documentai_install_with_bom] -->
     <dependency>