Bulk function upgrades

[liamfallon]

Original issue URL: https://api.github.com/repos/kptdev/kpt/issues/3309
Original issue user: https://github.com/bgrant0607
Original issue created at: 2022-06-13T14:34:37Z
Original issue last updated at: 2023-01-26T04:46:50Z
Original issue body: Also mentioned here: kptdev/kpt#2528 (comment)

We'll want to surface available function upgrades similar to available package upgrades.

We'll want to suggest updates in upstream packages first. This would be easier if we separated upstream and downstream functions (kptdev/kpt#2544).

Original issue comments:
Comment user: bgrant0607
Comment created at: 2022-07-08T14:53:12Z
Comment last updated at: 2022-07-08T14:53:12Z
Comment body: This maybe could be implemented by running a patch function in bulk: #3350.