Only runs a part of targets when run dist release in PRs

[Myriad-Dreamin]

I have 14 targets to build using cargo-dist, but it is too expensive to verify build them all in PRs. I would like to only build 3 of them to allow a minimal verification and for most people who want to get artifacts from PR's GitHub actions:

• x86 linux
• x86 windows
• apple darwin