chore: regenerate README (#465)

This PR was generated using Autosynth. 🌈


<details><summary>Log from Synthtool</summary>

```
2021-05-26 21:42:59,457 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-container/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-05-26 21:43:00,681 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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https://source.cloud.google.com/results/invocations/8e234788-048c-4797-915f-758bd257df07/targets

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.github/readme/synth.metadata/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-container.git",
-        "sha": "cb6efae4e896ca0acfc11f10b7a18d5a3ecaa569"
+        "sha": "bc1a49f7bdcdf2a2d6ce2394001321cf11394eb5"
       }
     },
     {

README.md

@@ -38,7 +38,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-container</artifactId>
-  <version>1.3.2</version>
+  <version>1.3.4</version>
 </dependency>
 
 ```