chore: regenerate README (#634)

This PR was generated using Autosynth. 🌈


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

```
2021-08-05 17:57:11,093 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-storage-nio/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-05 17:57:12,288 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/23b0b449-e766-4b59-a9d6-651ca05e9174/targets

- [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

Author: yoshi-automation

java-storage-nio/.github/readme/synth.metadata/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-storage-nio.git",
-        "sha": "5d33740b09dae94eef61488197e69c6f19fd2556"
+        "sha": "df4a7c4625e55d12eb8111f2c73d42152ba50bf8"
       }
     },
     {

java-storage-nio/README.md

@@ -45,7 +45,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-nio</artifactId>
-  <version>0.123.3</version>
+  <version>0.123.4</version>
 </dependency>
 
 ```