V0.2.1 (apache#187)

* add v0.2.1 change list (apache#181)

* add v0.2.1 change list

* keep v0.2.0 change list

* pixiu-0.2.1-rc2 (apache#186)

* add v0.2.1 change list (apache#181) (apache#182)

* add v0.2.1 change list

* keep v0.2.0 change list

* Change the image of mascot (apache#185)

* change the image of the mascot

* add old logo

Co-authored-by: alchemy-lee <2769566951@qq.com>

Co-authored-by: alchemy-lee <2769566951@qq.com>
Former-commit-id: 5c98b5e