chore: regenerate README (#370)

This PR was generated using Autosynth. 🌈


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

```
2021-03-18 01:36:16,384 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-datastore/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-18 01:36:17,302 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/ec651000-ed7a-43e4-a323-dcec3bf7be92/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-datastore.git",
-        "sha": "a6cee5c8dee68e2d1f291bbd6e709c175ce831f7"
+        "sha": "d6a2dde141365ea465f2cb280947f7b7c088485b"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "2e7bd5cc66a3f0b90ce1c150eb35c89eeb9872d6"
+        "sha": "78437c732a60c64895778697b078497b0988346c"
       }
     }
   ]

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>19.0.0</version>
+      <version>19.2.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
@@ -45,18 +45,18 @@ 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-datastore'
 ```
 If you are using Gradle without BOM, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-datastore:1.105.9'
+compile 'com.google.cloud:google-cloud-datastore:1.106.0'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-datastore" % "1.105.9"
+libraryDependencies += "com.google.cloud" % "google-cloud-datastore" % "1.106.0"
 ```
 
 ## Authentication