Update to 0.8.0 (#1918)

* Create new branch 0.8.0 and change preload_table to preload_collection

Signed-off-by: jinhai <hai.jin@zilliz.com>

* Fix format

Signed-off-by: JinHai-CN <hai.jin@zilliz.com>

* Update CHANGELOG

Signed-off-by: jinhai <hai.jin@zilliz.com>

* Update CHANGELOG

Signed-off-by: jinhai <hai.jin@zilliz.com>

* update helm version

Signed-off-by: zw <zw@zilliz.com>

* Update CHANGELOG

Signed-off-by: jinhai <hai.jin@zilliz.com>

Co-authored-by: zw <zw@zilliz.com>