Need a simple way for swiftly to import only active GPG keys

[rayx]

Is your feature request related to a problem? Please describe

Swift.org website provides all-keys.asc file at https://www.swift.org/keys/all-keys.asc. The file is used by swiftly project to verify toolchain file signature. However, as the file contains all keys (including those expired), it generates noise on user system. An issue was reported against swiftly. See: swiftlang/swiftly#148. During the discussion on that issue, it's suggested that Swift.org should provide an asc file containing only active keys.

Describe the solution you'd like

Swift.org should provide an asc file containing only active keys

Describe alternatives you've considered

Alt 1) Skip expired keys when importing keys from all-keys.asc. Unfortunately gpg doesn't have an out-of-box support for this. According to its man page, while its filter expression supports expired property, that only works for --export-filter, not --import-filter.

Alt 2) Swift website has a page for active GPG keys (https://www.swift.org/keys/active/). But it's not friendly for script to parse.

Additional context

N/A