chore: regenerate README (#894)

This PR was generated using Autosynth. 🌈


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

```
2021-07-01 20:45:09,456 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigtable/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-07-01 20:45:10,697 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/b2e99828-7c42-4fef-8b81-4f232bcb7797/targets

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Author: yoshi-automation

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigtable.git",
-        "sha": "7e2c3427b29cd22a6caccf7f4409ac5cd2f6c4ee"
+        "sha": "d2ca9c62f3fcb9c79c97ef8a73bad3a0e7555afc"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "9763f20e4b7bb1091082462b2f7970e965d0d414"
+        "sha": "39652e3948f455fd0b77535a0145eeec561a3706"
       }
     }
   ]

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-bigtable</artifactId>
-  <version>1.27.0</version>
+  <version>1.27.1</version>
 </dependency>
 
 ```
@@ -51,12 +51,12 @@ compile 'com.google.cloud:google-cloud-bigtable'
 ```
 If you are using Gradle without BOM, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-bigtable:1.27.0'
+compile 'com.google.cloud:google-cloud-bigtable:1.27.1'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-bigtable" % "1.27.0"
+libraryDependencies += "com.google.cloud" % "google-cloud-bigtable" % "1.27.1"
 ```
 
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