chore: regenerate README (#611)

This PR was generated using Autosynth. 🌈


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

```
2021-03-15 15:33:50,865 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-asset/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-15 15:33:51,753 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/14baec43-72a9-4d72-8dbf-ab2e599b4840/targets

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

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-asset.git",
-        "sha": "ca3edb3cd962171c20cd6df8444b41dd0a7586e4"
+        "sha": "3f0dcfab6616264727a4ec0e859ecab5838d8ec4"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "2e7bd5cc66a3f0b90ce1c150eb35c89eeb9872d6"
+        "sha": "2c54c473779ea731128cea61a3a6c975a08a5378"
       }
     }
   ]

README.md

@@ -52,12 +52,12 @@ compile 'com.google.cloud:google-cloud-asset'
 ```
 If you are using Gradle without BOM, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-asset:2.3.2'
+compile 'com.google.cloud:google-cloud-asset:2.3.3'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-asset" % "2.3.2"
+libraryDependencies += "com.google.cloud" % "google-cloud-asset" % "2.3.3"
 ```
 
 ## Authentication