chore: regenerate README (#395)

This PR was generated using Autosynth. 🌈


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

```
2021-02-16 19:42:28,699 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-errorreporting/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-02-16 19:42:30,350 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/f9ce5dfe-82cb-48af-9e44-34b1e9b791b0/targets

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Author: yoshi-automation

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

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-errorreporting.git",
-        "sha": "975023840885024eb66d3693ba206952c05b3cc0"
+        "sha": "18b6246119ee1ec41ce2535366b6c91b39b4142c"
       }
     },
     {

README.md

@@ -73,12 +73,12 @@ compile 'com.google.cloud:google-cloud-errorreporting'
 ```
 If you are using Gradle without BOM, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-errorreporting:0.120.13-beta'
+compile 'com.google.cloud:google-cloud-errorreporting:0.120.14-beta'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-errorreporting" % "0.120.13-beta"
+libraryDependencies += "com.google.cloud" % "google-cloud-errorreporting" % "0.120.14-beta"
 ```
 
 ## Authentication