deps: add gson explicitly. move gson and slf4j-api version to parent pom.

Author: zhumin8

oauth2_http/pom.xml

@@ -250,7 +250,12 @@
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
-      <version>2.0.16</version>
+      <version>${project.slf4j.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <version>${project.gson.version}</version>
     </dependency>
     <!--    Logback  for testing -->
     <dependency>
@@ -272,12 +277,6 @@
       <artifactId>junit</artifactId>
       <scope>test</scope>
     </dependency>
-    <dependency>
-      <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest-core</artifactId>
-      <version>1.3</version>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-core</artifactId>

pom.xml

@@ -76,6 +76,8 @@
     <project.findbugs.version>3.0.2</project.findbugs.version>
     <deploy.autorelease>false</deploy.autorelease>
     <project.error-prone.version>2.36.0</project.error-prone.version>
+    <project.gson.version>2.11.0</project.gson.version>
+    <project.slf4j.version>2.0.16</project.slf4j.version>
   </properties>
 
   <dependencyManagement>