chore(deps): update dependency hl7.fhir.base to v6

Author: renovate[bot]

src/FhirOperationDefinitionGen/FhirOperationDefinitionGen.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4" PrivateAssets="all" />
     <PackageReference Include="Hl7.Fhir.R4" Version="5.7.0" PrivateAssets="all"
       GeneratePathProperty="true" />
-    <PackageReference Include="Hl7.Fhir.Base" Version="5.7.0" PrivateAssets="all"
+    <PackageReference Include="Hl7.Fhir.Base" Version="6.0.1" PrivateAssets="all"
       GeneratePathProperty="true" />
     <PackageReference Include="Scriban" Version="5.9.1" PrivateAssets="all"
       GeneratePathProperty="true" />