chore: regenerate README (#605)

This PR was generated using Autosynth. 🌈


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

```
2021-08-25 23:39:44,589 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-document-ai/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-25 23:39:45,609 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 @@
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         "name": ".",
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-        "sha": "fde99cac1da510aba355f15fe34fd123238202b8"
+        "sha": "2ded9f05a6b474557bda01d87567081ab60c6053"
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     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "a01e1a0bf70754f51450958b966bd673945d1e6e"
+        "sha": "31728d872f50e439ded2f67fa8d67955b26a4e35"
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   ]

README.md

@@ -57,13 +57,13 @@ compile 'com.google.cloud:google-cloud-document-ai'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:google-cloud-document-ai:2.0.2'
+compile 'com.google.cloud:google-cloud-document-ai:2.0.3'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-document-ai" % "2.0.2"
+libraryDependencies += "com.google.cloud" % "google-cloud-document-ai" % "2.0.3"
 ```
 
 ## Authentication