Changed requirement to python 3.10 (#3496)

### What problem does this PR solve?

Changed requirement to python 3.10.
Changed image base to Ubuntu 22.04 since it contains python 3.10.

### Type of change

- [x] Refactoring

rag/utils/doc_store_conn.py

@@ -44,7 +44,7 @@ class SparseVector:
 class MatchTextExpr(ABC):
     def __init__(
         self,
-        fields: str,
+        fields: list[str],
         matching_text: str,
         topn: int,
         extra_options: dict = dict(),