[Chapel Merge] Add 15 day update delay (cooldown) to Dependabot

Branch: refs/heads/main
Revision: aca1b827fd31a6a36f63c5ec530ec8aae9c9dc73
Author: arifthpe
Link: Add 15 day update delay (cooldown) to Dependabot by arifthpe · Pull Request #28890 · chapel-lang/chapel · GitHub
Log Message:
Add 15 day update delay (cooldown) to Dependabot (#28890)

Set the cooldown option on
Dependabot

to be more conservative in Actions updates, to reduce risk of being
bitten by a supply-chain attack.

Currently set to 15 days.

[reviewed by @jabraham17 , thanks!]

Compare: Comparing ca0e4ddd01b4a354d82b184cdcca3ccf518c3fae...3bc391b10e8c85aa154aabdcdc23318ec1be8eb6 · chapel-lang/chapel · GitHub

Diff:
M .github/dependabot.yml
https://github.com/chapel-lang/chapel/pull/28890.diff