chore: regenerate README (googleapis#676)

This PR was generated using Autosynth. 🌈


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

```
2021-08-31 20:50:47,344 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-storage-nio/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-31 20:50:48,560 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/57cedac8-baa7-4d7c-aa4d-24615c510fcd/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-storage-nio.git",
-        "sha": "2f20642bbb0898830cb9d1d521d4ee675d1e475a"
+        "sha": "40f2c3298472546973f118520699fc41a0a90df2"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "31728d872f50e439ded2f67fa8d67955b26a4e35"
+        "sha": "9a238a0623879c3de129a376c6085d4a862f6eb9"
       }
     }
   ]

README.md

@@ -55,12 +55,12 @@ If you are using Gradle 5.x or later, add this to your dependencies
 ```Groovy
 implementation platform('com.google.cloud:libraries-bom:22.0.0')
 
-compile 'com.google.cloud:google-cloud-nio'
+implementation 'com.google.cloud:google-cloud-nio'
 ```
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:google-cloud-nio:0.123.8'
+implementation 'com.google.cloud:google-cloud-nio:0.123.8'
 ```
 
 If you are using SBT, add this to your dependencies