Remove Langchain::Vectorsearch::Epsilla class (patterns-ai-core#997)

Author: andreibondarev

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 ## [Unreleased]
 - [COMPAT] [https://github.com/patterns-ai-core/langchainrb/pull/980] Suppress a Ruby 3.4 warning for URI parser.
+- [BREAKING] [https://github.com/patterns-ai-core/langchainrb/pull/997] Remove `Langchain::Vectorsearch::Epsilla` class
 
 ## [0.19.5]
 - [BREAKING] [https://github.com/patterns-ai-core/langchainrb/pull/859] Add metadata support to PgVector storage