chore(deps): bump dev.langchain4j:langchain4j-community-bom

Bumps [dev.langchain4j:langchain4j-community-bom](https://github.com/langchain4j/langchain4j-community) from 1.2.0-beta7 to 1.2.0-beta8.
- [Release notes](https://github.com/langchain4j/langchain4j-community/releases)
- [Commits](https://github.com/langchain4j/langchain4j-community/commits/1.2.0-beta8)

---
updated-dependencies:
- dependency-name: dev.langchain4j:langchain4j-community-bom
  dependency-version: 1.2.0-beta8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

build.gradle.kts

@@ -113,7 +113,7 @@ dependencies {
     implementation("dev.langchain4j:langchain4j-mistral-ai")
     implementation("dev.langchain4j:langchain4j-bedrock")
 
-    implementation(platform("dev.langchain4j:langchain4j-community-bom:1.2.0-beta7"))
+    implementation(platform("dev.langchain4j:langchain4j-community-bom:1.2.0-beta8"))
     // The Baidu Qianfan Large Model Platform, including the ERNIE series, can be accessed at https://docs.langchain4j.dev/integrations/language-models/qianfan/.
     implementation("dev.langchain4j:langchain4j-community-qianfan")