chore: regenerate README (#288)

This PR was generated using Autosynth. 🌈


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

```
2021-05-17 23:23:33,824 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-mediatranslation/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-05-17 23:23:35,210 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/c8e09330-e675-491d-80e0-215495a3200e/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-mediatranslation.git",
-        "sha": "24cddc775d76b7138c4f5bc0dd1f191d7cae6fad"
+        "sha": "c09a95591fef62d4150fc7ec4690867a065fa5bc"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "06a8cd0ff7e81b05e6c503eab510ec622384caa7"
+        "sha": "c86c7a60985644eab557949363a38301d40d78d2"
       }
     }
   ]

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-mediatranslation:0.3.2'
+compile 'com.google.cloud:google-cloud-mediatranslation:0.4.0'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-mediatranslation" % "0.3.2"
+libraryDependencies += "com.google.cloud" % "google-cloud-mediatranslation" % "0.4.0"
 ```
 
 ## Authentication