chore: regenerate README (#640)

This PR was generated using Autosynth. 🌈 <details><summary>Log from Synthtool</summary> ``` 2021-04-12 14:27:23,815 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-asset/.github/readme/synth.py. On branch autosynth-readme nothing to commit, working tree clean 2021-04-12 14:27:25,095 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/3fc946da-c0d3-4f34-aa0f-7583a68ef0a5/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-asset.git",
- "sha": "04e3e2306641a27a7fb55093e1118af8a6052a83"
+ "sha": "dc1e556d396bd1f979b0956931e172de2bd0a498"
  }
  },
  {

README.md

@@ -46,7 +46,7 @@ If you are using Maven without BOM, add this to your dependencies:
 
 If you are using Gradle 5.x or later, add this to your dependencies
 ```Groovy
-implementation platform('com.google.cloud:libraries-bom:19.2.1')
+implementation platform('com.google.cloud:libraries-bom:20.0.0')
 
 compile 'com.google.cloud:google-cloud-asset'
 ```