chore: declare first-party-dependencies version as a property (#7287)

* chore: declare first-party-dependencies version as a property

Author: suztomo

libraries-bom/pom.xml

@@ -44,6 +44,7 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <first-party-dependencies.version>3.54.1</first-party-dependencies.version>
   </properties>
 
   <distributionManagement>
@@ -76,7 +77,7 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>first-party-dependencies</artifactId>
-        <version>3.54.1</version>
+        <version>${first-party-dependencies.version}</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>