Make duplicate deb/rpm packages so we can sign them with the new PMC key

[jkoritzinsky]

Contributes to dotnet/arcade#16047

Make duplicate deb/rpm packages so we can sign them with the new PMC key

Description

PMC has added a new signing key for packages published to repositories for new Linux distributions they will add support for, such as Debian 13 and SLES vNext. Packages pushed to these feeds must be signed with the new key. Existing feeds will maintain the same keys. The .NET signing infrastructure requires us to have separate copies of the package files to have them signed with different keys. This PR introduces separate copies of the DEB and RPM installers to be signed with the new signing keys.

Contributes to dotnet/arcade#16047

Customer Impact

Without this change, we can't ship .deb installers for Debian 13. With this change, we can.

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

[Justify the selection above]

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

[marcpopMSFT]

@jkoritzinsky what's the timeframe for this? They are trying to get initial builds for September already.

[marcpopMSFT]

Also, will there need to be changes in staging or release to handle this and ensure we ship the right ones?

[jkoritzinsky]

This can wait at least a week if need be (we can't do anything with these new packages until Microbuild can sign with the new cert). And yes, we will need changes in release/staging to sign with the correct cert.

@leecow would know better than I when this needs to be in by.

[leecow]

We need to have this work done for the September releases.

[jkoritzinsky]

/backport to release/8.0.4xx

[github-actions]

Started backporting to release/8.0.4xx: https://github.com/dotnet/installer/actions/runs/17839994515

[mmitche]

/backport to release/8.0.3xx

[github-actions]

Started backporting to release/8.0.3xx: https://github.com/dotnet/installer/actions/runs/18040699091