chore: regenerate README versions (#168)

This PR was generated using Autosynth. 🌈

Synth log will be available here:
https://source.cloud.google.com/results/invocations/a9613835-4ca9-4e24-a145-9a27c369c58d/targets

- [ ] To automatically regenerate this PR, check this box.

README.md

@@ -17,7 +17,7 @@ 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>5.5.0</version>
+      <version>5.7.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>

synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-iamcredentials.git",
-        "sha": "7f82551fe333d60c5ab76666f856a573f1c3483f"
+        "sha": "62164d97c297cc64aa17ec9cfc00e3286660bb31"
       }
     },
     {