chore: regenerate README (#305)

This PR was generated using Autosynth. 🌈


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

```
2020-11-09 17:44:20,858 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-errorreporting/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working directory clean
2020-11-09 17:44:21,780 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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Author: yoshi-automation

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-errorreporting.git",
-        "sha": "544f2311d23ed52c5d5017bb0553372ace7b6c2a"
+        "sha": "96e2e0549d4717f780badd31f16b90f11c91c849"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "2c8aecedd55b0480fb4e123b6e07fa5b12953862"
+        "sha": "1f1148d3c7a7a52f0c98077f976bd9b3c948ee2b"
       }
     }
   ]

README.md

@@ -60,18 +60,18 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-errorreporting</artifactId>
-  <version>0.120.5-beta</version>
+  <version>0.120.7-beta</version>
 </dependency>
 
 ```
 
 If you are using Gradle, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-errorreporting:0.120.5-beta'
+compile 'com.google.cloud:google-cloud-errorreporting:0.120.7-beta'
 ```
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-errorreporting" % "0.120.5-beta"
+libraryDependencies += "com.google.cloud" % "google-cloud-errorreporting" % "0.120.7-beta"
 ```
 
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