chore: regenerate README (#59)

This PR was generated using Autosynth. 🌈


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

```
2021-06-16 19:57:48,689 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-domains/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-06-16 19:57:49,886 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

Full log will be available here:
https://source.cloud.google.com/results/invocations/35a80d60-b746-4567-a97b-b790ff0f678f/targets

- [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-domains.git",
-        "sha": "bdecc457973b89d6462de0f3ddee9e6cee909877"
+        "sha": "333ae2f71cfeabd8a4b9c62c77bba7c12bcdf616"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5cae043787729a908ed0cab28ca27baf9acee3c4"
+        "sha": "8f76a885deaaf2fe234daeba4a8cc4d1b3de8086"
       }
     }
   ]

README.md

@@ -20,7 +20,7 @@ If you are using Maven, add this to your pom.xml file:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-domains</artifactId>
-  <version>0.2.0</version>
+  <version>0.2.1</version>
 </dependency>
 
 ```