chore: regenerate README (#228)

This PR was generated using Autosynth. 🌈


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

```
2021-04-09 23:10:28,499 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-workflows/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-04-09 23:10:29,775 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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java-workflows/.github/readme/synth.metadata/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-workflows.git",
-        "sha": "edb06f32ce915cc1994f7993951ba013bebb8759"
+        "sha": "c3cef693a677061fcb1b1585bebe1fa2c39b4ed9"
       }
     },
     {

java-workflows/README.md

@@ -27,12 +27,12 @@ If you are using Maven, add this to your pom.xml file:
 
 If you are using Gradle without BOM, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-workflows:0.3.0'
+compile 'com.google.cloud:google-cloud-workflows:0.3.1'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-workflows" % "0.3.0"
+libraryDependencies += "com.google.cloud" % "google-cloud-workflows" % "0.3.1"
 ```
 
 ## Authentication