chore: regenerate README (#742)

This PR was generated using Autosynth. 🌈


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

```
2020-12-16 16:47:40,269 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquerystorage/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2020-12-16 16:47:41,133 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/06960d9e-0a19-4a77-9978-d38f7d9f8d61/targets

- [ ] To automatically regenerate this PR, check this box.

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigquerystorage.git",
-        "sha": "c405157cd6704981d58c73f8b1918e0e06731f33"
+        "sha": "423e8bf6c4841ee571dd8312d3b8318271494021"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "996775eca5fd934edac3c2ae34b80ff0395b1717"
+        "sha": "3f67ceece7e797a5736a25488aae35405649b90b"
       }
     }
   ]

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-bigquerystorage</artifactId>
-  <version>1.7.0</version>
+  <version>1.7.2</version>
 </dependency>
 
 ```