chore: regenerate README (#173)

This PR was generated using Autosynth. 🌈


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

```
2021-08-12 23:13:00,420 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-retail/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-12 23:13:01,640 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/0e4fbd5e-2769-46bb-9a05-2c488800b969/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-retail.git",
-        "sha": "9f945bd768241558a5365a958a7588de8067af71"
+        "sha": "dbdbd64f15166bb3585e25cd96df787a34b3ae98"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "df7fc1e3a6df4316920ab221431945cdf9aa7217"
+        "sha": "ff01716e16d2c6e87eaf87197b753ac9fcbbed5d"
       }
     }
   ]

README.md

@@ -19,21 +19,21 @@ If you are using Maven, add this to your pom.xml file:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-retail</artifactId>
-  <version>1.2.0</version>
+  <version>1.2.1</version>
 </dependency>
 
 ```
 
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:google-cloud-retail:1.2.0'
+compile 'com.google.cloud:google-cloud-retail:1.2.1'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-retail" % "1.2.0"
+libraryDependencies += "com.google.cloud" % "google-cloud-retail" % "1.2.1"
 ```
 
 ## Authentication