fix: remove obsoleted 'version' elements in compose files (#5553)

docker/docker-compose.chroma.yaml

-version: '3'
 services:
   # Chroma vector store.
   chroma:

docker/docker-compose.middleware.yaml

-version: '3'
 services:
   # The postgres database.
   db:

docker/docker-compose.opensearch.yml

-version: '3'
 services:
   opensearch: # This is also the hostname of the container within the Docker network (i.e. https://opensearch/)
     image: opensearchproject/opensearch:latest # Specifying the latest available image - modify if you want a specific version

docker/docker-compose.oracle.yaml

-version: '3'
 services:
   # oracle 23 ai vector store.
   oracle:

docker/docker-compose.pgvecto-rs.yaml

-version: '3'
 services:
   # The pgvecto—rs database.
   pgvecto-rs:

docker/docker-compose.pgvector.yaml

-version: '3'
 services:
   # Qdrant vector store.
   pgvector:

docker/docker-compose.qdrant.yaml

-version: '3'
 services:
   # Qdrant vector store.
   qdrant:

docker/docker-compose.yaml

-version: '3'
 services:
   # API service
   api: