chore: regenerate README (#368)

This PR was generated using Autosynth. 🌈


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

```
2021-03-29 13:59:07,304 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-accessapproval/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-29 13:59:08,555 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/f42d5066-2a62-4d70-a6c7-b7615826ace9/targets

- [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-accessapproval.git",
-        "sha": "5a50ce89023efbee6cba1227cd7086a4765f8d3c"
+        "sha": "f5989510cd455a7e4ea2e16e7f07e983be0e6201"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "c84c8f156e09702e1c8946bfb9746e6f5892cf27"
+        "sha": "60fc32cc950c20cfdd774b846a4a7dc5d1e4d0ef"
       }
     }
   ]

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>19.0.0</version>
+      <version>19.2.1</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>