fix dependency management

Author: chingor13

java-datastore/google-cloud-datastore/pom.xml

@@ -17,18 +17,6 @@
   <properties>
     <site.installationModule>google-cloud-datastore</site.installationModule>
   </properties>
-  <dependencyManagement>
-    <dependencies>
-      <dependency>
-        <!-- Artifacts from google-cloud-java monorepo -->
-        <groupId>com.google.cloud</groupId>
-        <artifactId>gapic-libraries-bom</artifactId>
-        <version>1.79.0-SNAPSHOT</version><!-- {x-version-update:gapic-libraries:current} -->
-        <type>pom</type>
-        <scope>import</scope>
-      </dependency>
-    </dependencies>
-  </dependencyManagement>
   <dependencies>
     <dependency>
       <groupId>com.google.api.grpc</groupId>