chore: regenerate README (#643)

This PR was generated using Autosynth. 🌈


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

```
2021-08-25 23:41:08,143 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-logging/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-25 23:41:09,133 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/78514624-dce5-42fa-bb43-e9aaa6042d83/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-logging.git",
-        "sha": "6b3ee2cf2db8bdca6262bd7bd60c0ba1df9e1c32"
+        "sha": "32c93953282ccd726a6fd91f9f1a6469f73d30ec"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "484b7ec7bdef3909589a83e3d763e7588cb8c37c"
+        "sha": "31728d872f50e439ded2f67fa8d67955b26a4e35"
       }
     }
   ]

README.md

@@ -57,13 +57,13 @@ compile 'com.google.cloud:google-cloud-logging'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:google-cloud-logging:3.0.1'
+compile 'com.google.cloud:google-cloud-logging:3.1.0'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-logging" % "3.0.1"
+libraryDependencies += "com.google.cloud" % "google-cloud-logging" % "3.1.0"
 ```
 
 ## Authentication