chore: regenerate README (#473)

This PR was generated using Autosynth. 🌈


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

```
2021-03-18 17:16:48,682 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-speech/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-18 17:16:49,736 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/88b5cab0-38c3-48f6-88c7-b076c0d0d8ac/targets

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

Author: yoshi-automation

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-speech.git",
-        "sha": "59d5abfd75d24e87bd5b98600dafcbf674316f54"
+        "sha": "648b74d3807dac1586ae15c21185ff285874dfb2"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "94686b06034ff6e11217236fcaa217ec6e24bc39"
+        "sha": "78437c732a60c64895778697b078497b0988346c"
       }
     }
   ]

README.md

@@ -46,7 +46,7 @@ If you are using Maven without BOM, add this to your dependencies:
 
 If you are using Gradle 5.x or later, add this to your dependencies
 ```Groovy
-implementation platform('com.google.cloud:libraries-bom:19.0.0')
+implementation platform('com.google.cloud:libraries-bom:19.2.0')
 
 compile 'com.google.cloud:google-cloud-speech'
 ```
@@ -158,6 +158,7 @@ has instructions for running the samples.
 | Recognize | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/Recognize.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/Recognize.java) |
 | Recognize Beta | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/RecognizeBeta.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/RecognizeBeta.java) |
 | Speech Adaptation | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/SpeechAdaptation.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/SpeechAdaptation.java) |
+| Speech Model Adaptation Beta | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/SpeechModelAdaptationBeta.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/SpeechModelAdaptationBeta.java) |
 | Speech Profanity Filter | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/SpeechProfanityFilter.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/SpeechProfanityFilter.java) |
 | Speech Transcribe Multi Region | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/SpeechTranscribeMultiRegion.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/SpeechTranscribeMultiRegion.java) |
 | Transcribe Context Classes | [source code](https://github.com/googleapis/java-speech/blob/master/samples/snippets/src/main/java/com/example/speech/TranscribeContextClasses.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-speech&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/speech/TranscribeContextClasses.java) |