feat: update `PGVectorStore` constructor parameters (#1225)

.changeset/twenty-dolphins-marry.md

examples/pg-vector-store/load-docs.ts

examples/pg-vector-store/query.ts

...s/llamaindex/e2e/node/vector-store/pg-vector-store.e2e.ts

packages/llamaindex/src/vector-store/PGVectorStore.ts