chore: regenerate README (#1286)

This PR was generated using Autosynth. 🌈


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

```
2021-09-02 23:26:42,107 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquerystorage/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-09-02 23:26:43,088 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/b9508c89-5db4-4c3f-901a-62925a3b11fd/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigquerystorage.git",
-        "sha": "0b5ef38a2f23cfe48653fcbf725ffdb05df46c2f"
+        "sha": "ac552766e1099fcf1b4504cdece7056e41ec54db"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5c0fa62eea9c33ebe61e582424b659eb264e1ba4"
+        "sha": "ad7fd76e17bf9494a3e47ff9cf445f61564432e0"
       }
     }
   ]

README.md

@@ -56,13 +56,13 @@ implementation 'com.google.cloud:google-cloud-bigquerystorage'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-bigquerystorage:2.1.1'
+implementation 'com.google.cloud:google-cloud-bigquerystorage:2.1.2'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-bigquerystorage" % "2.1.1"
+libraryDependencies += "com.google.cloud" % "google-cloud-bigquerystorage" % "2.1.2"
 ```
 
 ## Authentication