Downgrade Jakarta Persistence to 3.1.0 for SB compatibility

Downgrade Jakarta Persistence to 3.1.0 for SB compatibility. Based this
decision on a Spring Boot GitHub issue and StackOverflow question:
SB issue: spring-projects/spring-boot#39753
SO question: https://stackoverflow.com/questions/78073522/spring-boot-3-2-2-entitymanagerfactory-interface-org-hibernate-sessionfactory-s

#171

Author: smcvb

pom.xml

@@ -50,7 +50,7 @@
         <spring.version>6.1.11</spring.version>
         <spring-boot.version>3.3.1</spring-boot.version>
         <!-- Database -->
-        <jakarta.persistence.version>3.2.0</jakarta.persistence.version>
+        <jakarta.persistence.version>3.1.0</jakarta.persistence.version>
         <!-- Serialization -->
         <jackson.version>2.17.2</jackson.version>
         <!-- Testing -->