update package version to 2.26.4

Author: cindy-peng

google-cloud-datastore-utils/pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-datastore-utils</artifactId>
-    <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:google-cloud-datastore:current} -->
+    <version>2.26.4</version><!-- {x-version-update:google-cloud-datastore:current} -->
     <packaging>jar</packaging>
     <name>Google Cloud Datastore Utilities</name>
     <url>https://github.com/googleapis/java-datastore</url>
@@ -13,7 +13,7 @@
     <parent>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-datastore-parent</artifactId>
-        <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:google-cloud-datastore:current} -->
+        <version>2.26.4</version><!-- {x-version-update:google-cloud-datastore:current} -->
     </parent>
     <properties>
         <site.installationModule>google-cloud-datastore-utils</site.installationModule>

grpc-google-cloud-datastore-v1/pom.xml

@@ -4,13 +4,13 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.api.grpc</groupId>
   <artifactId>grpc-google-cloud-datastore-v1</artifactId>
-  <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:grpc-google-cloud-datastore-v1:current} -->
+  <version>2.26.4</version><!-- {x-version-update:grpc-google-cloud-datastore-v1:current} -->
   <name>grpc-google-cloud-datastore-v1</name>
   <description>GRPC library for google-cloud-datastore</description>
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-datastore-parent</artifactId>
-    <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:google-cloud-datastore:current} -->
+    <version>2.26.4</version><!-- {x-version-update:google-cloud-datastore:current} -->
   </parent>
   <dependencies>
     <dependency>

pom.xml

@@ -179,12 +179,12 @@
       <dependency>
         <groupId>com.google.api.grpc</groupId>
         <artifactId>grpc-google-cloud-datastore-v1</artifactId>
-        <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:grpc-google-cloud-datastore-v1:current} -->
+        <version>2.26.4</version><!-- {x-version-update:grpc-google-cloud-datastore-v1:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-datastore-utils</artifactId>
-        <version>2.26.4-SNAPSHOT</version><!-- {x-version-update:google-cloud-datastore-utils:current} -->
+        <version>2.26.4</version><!-- {x-version-update:google-cloud-datastore-utils:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.cloud.datastore</groupId>