* support HNSW deletion on nmslib
Signed-off-by: Nlichengming <chengming.li@zilliz.com>

* update changelog
Signed-off-by: Nlichengming <chengming.li@zilliz.com>

* fix lint error on test_hnsw.cpp
Signed-off-by: Nlichengming <chengming.li@zilliz.com>
Co-authored-by: Nlichengming <chengming.li@zilliz.com>