chore: regenerate README (#851)

This PR was generated using Autosynth. 🌈


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

```
2021-05-24 02:15:06,904 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquerydatatransfer/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-05-24 02:15:08,105 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/a4397b71-4ae0-4662-af49-86c18a89c5bc/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-bigquerydatatransfer.git",
-        "sha": "07bb7b3d07ee6ece8eb3022618b5e40faa41d3b5"
+        "sha": "23062d97bcdf649e6f971e92a6642d004d4695f8"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "7332178a11ddddc91188dc0f25bca1ccadcaa6c6"
+        "sha": "bb5ef5a99df6d439c63fddf0f7b6fe58e0679b10"
       }
     }
   ]

README.md

@@ -38,7 +38,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-bigquerydatatransfer</artifactId>
-  <version>1.2.16</version>
+  <version>1.2.17</version>
 </dependency>
 
 ```