Update dependency ca.uhn.hapi.fhir:hapi-fhir-base to v8.4.0

Author: renovate[bot]

pom.xml

@@ -36,7 +36,7 @@
         <dependency>
             <groupId>ca.uhn.hapi.fhir</groupId>
             <artifactId>hapi-fhir-base</artifactId>
-            <version>8.0.0</version>
+            <version>8.4.0</version>
         </dependency>
         <dependency>
             <groupId>ca.uhn.hapi.fhir</groupId>