Bump fhir.version from 5.4.2 to 6.8.4

Bumps `fhir.version` from 5.4.2 to 6.8.4.

Updates `ca.uhn.hapi.fhir:hapi-fhir-base` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-client` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-structures-r5` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-structures-r4` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-structures-dstu2` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-validation` from 5.4.2 to 6.8.4

Updates `ca.uhn.hapi.fhir:hapi-fhir-validation-resources-r4` from 5.4.2 to 6.8.4

---
updated-dependencies:
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-base
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-client
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-structures-r5
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-structures-r4
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-structures-dstu2
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-validation
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: ca.uhn.hapi.fhir:hapi-fhir-validation-resources-r4
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

pom.xml

@@ -17,7 +17,7 @@
     <properties>
         <java.version>1.8</java.version>
         <kotlin.version>1.9.10</kotlin.version>
-        <fhir.version>5.4.2</fhir.version>
+        <fhir.version>6.8.4</fhir.version>
     </properties>
 
     <dependencies>