chore: regenerate README versions (#186)

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README.md

@@ -20,7 +20,7 @@ If you are using Maven with [BOM][libraries-bom], add this to your pom.xml file
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>libraries-bom</artifactId>
-      <version>5.3.0</version>
+      <version>5.6.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>

synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-datalabeling.git",
-        "sha": "fda47efff5633ae0ca206870d80d0dc4211b0979"
+        "sha": "ddec4b0d477c5636d3d3cf80f0e4aeb9c97fa83e"
       }
     },
     {