chore: regenerate README (#242)

This PR was generated using Autosynth. 🌈


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

```
2021-08-11 16:15:27,121 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-pubsublite-spark/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-11 16:15:28,203 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/c609d9e9-7062-4c8b-a16a-f89847b4b4f8/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-pubsublite-spark.git",
-        "sha": "d39175b2d0a642186933696734ee16867cb67e76"
+        "sha": "949b2c0dc00344cd9fba9a7113e9ea11b511cf88"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "3d32990b6f4b57be77455e3ca89e6e21cd0c06b3"
+        "sha": "6252f2cd074c38f37b44abe5e96d128733eb1b61"
       }
     }
   ]

README.md

@@ -22,20 +22,20 @@ If you are using Maven, add this to your pom.xml file:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>pubsublite-spark-sql-streaming</artifactId>
-  <version>0.3.0</version>
+  <version>0.3.1</version>
 </dependency>
 ```
 
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:pubsublite-spark-sql-streaming:0.3.0'
+compile 'com.google.cloud:pubsublite-spark-sql-streaming:0.3.1'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "pubsublite-spark-sql-streaming" % "0.3.0"
+libraryDependencies += "com.google.cloud" % "pubsublite-spark-sql-streaming" % "0.3.1"
 ```
 
 ## Authentication