chore: regenerate README (#535)

This PR was generated using Autosynth. 🌈


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

```
2020-11-21 09:12:06,254 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquerydatatransfer/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working directory clean
2020-11-21 09:12:07,170 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/2d912724-0a3b-402b-884a-978e52c36e52/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigquerydatatransfer.git",
-        "sha": "caac326028df9ff51e3f68c4159e2fff5828c6cd"
+        "sha": "95f5a9cd2949bc8d382c704a3bc357b99a90364e"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "68742c6016bf0d16948a572633d17955a8737414"
+        "sha": "91b34d7ffc37581e03eec8b16d08b84e46b82bbe"
       }
     }
   ]

README.md

@@ -45,11 +45,11 @@ If you are using Maven without BOM, add this to your dependencies:
 
 If you are using Gradle, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-bigquerydatatransfer:1.0.19'
+compile 'com.google.cloud:google-cloud-bigquerydatatransfer:1.0.20'
 ```
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-bigquerydatatransfer" % "1.0.19"
+libraryDependencies += "com.google.cloud" % "google-cloud-bigquerydatatransfer" % "1.0.20"
 ```
 
 ## Authentication