chore: regenerate README (#245)

This PR was generated using Autosynth. 🌈


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

```
2020-10-30 23:39:44,106 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-accessapproval/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working directory clean
2020-10-30 23:39:45,094 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/6806f125-ad0d-4851-addf-1ab53d895240/targets

- [ ] To automatically regenerate this PR, check this box.

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-accessapproval.git",
-        "sha": "a4b4143ee94d70a5486d96b9df2903fbba57e0d6"
+        "sha": "e87383bc89acb99819b5e639fb7987ae07d6d815"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "ea52b8a0bd560f72f376efcf45197fb7c8869120"
+        "sha": "b19b401571e77192f8dd38eab5fb2300a0de9324"
       }
     }
   ]

README.md

@@ -17,7 +17,7 @@ If you are using Maven with [BOM][libraries-bom], add this to your pom.xml file
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>libraries-bom</artifactId>
-      <version>13.3.0</version>
+      <version>13.4.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>