Debian 13 (trixie) warns about expiring signing certificate
`apt` clients from Debian 13 warn that the signing key type that ProGet uses will be rejected in a few months (declines access to repository). This message is also visible by our customers. Because we need to roll out the signing keys to our customers, changing it requires action by our customer side and is not great for the relationship. At the moment we have a few day window where we can swap keys easily before we onboard our customer base.
Warning printed by `apt update`:
```
Warning: https://proget.server.corp/debian/cloud/dists/trixie/InRelease: Policy will reject signature within a year, see --audit for details
```
Warning printed by `apt update --audit`:
```
Warning: https://proget.corp/debian/cloud/dists/trixie/InRelease: Policy will reject signature within a year, see --audit for details
Audit: https://proget.corp/debian/cloud/dists/trixie/InRelease: Sub-process /usr/bin/sqv returned an error code (1), error message is:
Error: Policy rejected packet type
Caused by:
Signature Packet v3 is not considered secure since 2026-02-01T00:00:00Z
```