Release Plan of v0.5.0

[Xuanwo]

Hi, @waynexia, @WenyXu, @Jefffrey and @progval, I propost to have a 0.5 release in which we include new arrow and opendal.

[waynexia]

• PR: chore: prepare release 0.5.0 #6

[Xuanwo]

Thank you @waynexia!