chore: regenerate README (googleapis#415)

This PR was generated using Autosynth. 🌈


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

```
2021-03-25 19:55:35,956 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-resourcemanager/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-25 19:55:37,205 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/8cb458b7-2135-4eda-841c-0003e4ae9ff8/targets

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

java-resourcemanager/.github/readme/synth.metadata/synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-resourcemanager.git",
-        "sha": "27cee9d683167eaf7a3027c40b19610c5e3a670b"
+        "sha": "2f806b2aa380722ab972cb7f92fababb8c554847"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "c84c8f156e09702e1c8946bfb9746e6f5892cf27"
+        "sha": "bb854b6c048619e3be4e8b8ce8ed10aa74ea78ef"
       }
     }
   ]

java-resourcemanager/README.md

@@ -20,7 +20,7 @@ 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>19.1.0</version>
+      <version>19.2.1</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>