fix: resolve issue #131 by fixing primary key type for user entity

Upgrade jacoco to 0.8.11 such that we can build with JDK 21

Upgrade Spring Boot to 3.2.1

Bugfix/pet-type-specialty-no-id-temp

Adding JDBC implementation for findPetTypeByName and findSpecialtiesByName along with respective unit tests

Adding JPA implementation for findPetTypeByName and findSpecialtiesByName

adding to respective repository interfaces and to service interface/implementation layer

Build & publish Docker image using GitHub Workflow

Fix "Create PetType endpoint returns wrong PetType ID" 

add getOwnersPet implementation

Add an addPet (POST /pets endpoint) implementation

ignoring unnecessarily generated surefire report

Fixed AbstractClinicServiceTests.java readme path

small fixes to openapi spec

fixed server url to be in line with server context
added specialty and pettypes in tags section
fixed tag typo (vets) in vet delete method
added some string to password example so it's not interpreted as number

Update jacoco plugin

ignoring unnecessarily generated jacoco report

Upgrading to SpringBoot v3