Update to released client library

Author: nirupa-kumar

texttospeech/beta/pom.xml

@@ -35,7 +35,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-texttospeech</artifactId>
-      <version>0.53.0-beta</version>
+      <version>0.55.0-beta</version>
     </dependency>
     <dependency>
       <groupId>net.sourceforge.argparse4j</groupId>