Add HikariCP dependency in test scope

Tests in doma-spring-boot-autoconfigure failed when bump Spring Boot to 2.3.RELEASE.
Cause is not enough dependency and component implementing javax.sql.DataSource is not created.

Author: backpaper0

doma-spring-boot-autoconfigure/pom.xml

@@ -56,6 +56,11 @@
             <artifactId>h2</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>HikariCP</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>