chore: regenerate README (#367)

This PR was generated using Autosynth. 🌈


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

```
2021-01-07 22:21:50,841 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-billingbudgets/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-01-07 22:21:51,680 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/e74d3df5-6f16-47ff-a1b9-89b500566a99/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-billingbudgets.git",
-        "sha": "901195a2a3d731840865fec341f8b61d30236917"
+        "sha": "855e91395df1dae81953c9d4ce78f1228cfc5e79"
       }
     },
     {

README.md

@@ -38,7 +38,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-billingbudgets</artifactId>
-  <version>1.0.1</version>
+  <version>1.0.3</version>
 </dependency>
 
 ```