fix(deps): update langchain4j monorepo to v1.8.0 (#39)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

conversational-ai4j-library/build.gradle

@@ -16,8 +16,8 @@ ext.libs = [mockito: 'org.mockito:mockito-core:5.20.0']
 
 dependencies {
   // LangChain4j with Ollama
-  implementation 'dev.langchain4j:langchain4j:1.7.1'
-  implementation 'dev.langchain4j:langchain4j-ollama:1.7.1'
+  implementation 'dev.langchain4j:langchain4j:1.8.0'
+  implementation 'dev.langchain4j:langchain4j-ollama:1.8.0'
 
   // Logging
   implementation 'org.slf4j:slf4j-api:2.0.17'