chore: regenerate README (#1362)

This PR was generated using Autosynth. 🌈 <details><summary>Log from Synthtool</summary> ``` 2021-08-18 23:49:14,594 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-spanner/.github/readme/synth.py. On branch autosynth-readme nothing to commit, working tree clean 2021-08-18 23:49:15,711 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/209ae509-c386-47e3-b26e-79d369d70ca4/targets - [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

Author: yoshi-automation

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

@@ -4,7 +4,7 @@
  "git": {
  "name": ".",
  "remote": "https://github.com/googleapis/java-spanner.git",
- "sha": "efb0f7ecf5a968805ef6f746907e4d8afe08a86a"
+ "sha": "72d5a43745b6db7206307a4309e15c813617263c"
  }
  },
  {

README.md

@@ -41,7 +41,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-spanner</artifactId>
- <version>6.11.0</version>
+ <version>6.11.1</version>
 </dependency>
 
 ```