chore: regenerate README (#262)

This PR was generated using Autosynth. 🌈


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

```
2021-05-19 21:05:49,455 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-workflows/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-05-19 21:05:50,717 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/1f6fed7a-68f5-4b5a-bcce-4c7554e2af29/targets

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Author: yoshi-automation

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-workflows.git",
-        "sha": "c72cc1dfe659d4748573e32d5ee13ae75767cce8"
+        "sha": "c3fb06c73388e857cedeca068714a9c2ec5f2bb9"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "4f4b1b9b8d8b52f1e9e4a76165896debce5ab7f1"
+        "sha": "bf148334fb9ee928d4c302d2aa32eb61252808d1"
       }
     }
   ]

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:0.4.1'
+compile 'com.google.cloud:google-cloud-workflows:0.4.2'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-workflows" % "0.4.1"
+libraryDependencies += "com.google.cloud" % "google-cloud-workflows" % "0.4.2"
 ```
 
 ## Authentication