chore: regenerate README (#572)

This PR was generated using Autosynth. 🌈


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

```
2020-12-15 22:39:13,531 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigtable/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2020-12-15 22:39:14,445 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/3f9ae92e-7ec9-4da2-95e0-49a01f5d0c1e/targets

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

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

@@ -0,0 +1,18 @@
+{
+  "sources": [
+    {
+      "git": {
+        "name": ".",
+        "remote": "https://github.com/googleapis/java-bigtable.git",
+        "sha": "d83350ead0c5ed897505a603c9c5cd9b014f5545"
+      }
+    },
+    {
+      "git": {
+        "name": "synthtool",
+        "remote": "https://github.com/googleapis/synthtool.git",
+        "sha": "996775eca5fd934edac3c2ae34b80ff0395b1717"
+      }
+    }
+  ]
+}

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>16.1.0</version>
+      <version>16.2.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
@@ -38,18 +38,18 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-bigtable</artifactId>
-  <version>1.19.2</version>
+  <version>1.19.1</version>
 </dependency>
 
 ```
 
 If you are using Gradle, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-bigtable:1.19.2'
+compile 'com.google.cloud:google-cloud-bigtable:1.19.1'
 ```
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-bigtable" % "1.19.2"
+libraryDependencies += "com.google.cloud" % "google-cloud-bigtable" % "1.19.1"
 ```
 
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