fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-8344146
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-8344149
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-7924769
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-7924772
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-8366323
- https://snyk.io/vuln/SNYK-JAVA-CAUHNHAPIFHIR-8366327
- https://snyk.io/vuln/SNYK-JAVA-COMMONSIO-8161190
- https://snyk.io/vuln/SNYK-JAVA-COMGOOGLEGUAVA-5710356

pom.xml

@@ -5,7 +5,7 @@
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
     <version>3.2.11</version>
-    <relativePath></relativePath>
+    <relativePath/>
     <!-- lookup parent from repository -->
   </parent>
   <groupId>com.semanticbits.measureservice</groupId>
@@ -147,7 +147,7 @@
     <dependency>
       <groupId>ca.uhn.hapi.fhir</groupId>
       <artifactId>hapi-fhir-structures-r4</artifactId>
-      <version>6.4.0</version>
+      <version>7.6.0</version>
       <exclusions>
         <exclusion>
           <artifactId>okhttp</artifactId>
@@ -281,7 +281,7 @@
                     </goals>
                   </pluginExecutionFilter>
                   <action>
-                    <ignore></ignore>
+                    <ignore/>
                   </action>
                 </pluginExecution>
               </pluginExecutions>