Improve package release assets

[dappnodedev]

Currently, package releases have too many assets, below I post a suggestion on how these releases could be cleaner:

├── avatar.png
├── content-hashes.json
├── lodestar.dnp.dappnode.eth_0.1.7.zip
│   ├── dappnode_package.json
│   ├── docker-compose.yml
│   ├── lodestar.dnp.dappnode.eth_0.1.7_linux-amd64.txz
│   └── lodestar.dnp.dappnode.eth_0.1.7_linux-arm64.txz
└── lodestar-holesky.dnp.dappnode.eth_0.1.9.zip
    ├── dappnode_package.json
    ├── docker-compose.yml
    ├── lodestar-holesky.dnp.dappnode.eth_0.1.9_linux-amd64.txz
    └── lodestar-holesky.dnp.dappnode.eth_0.1.9_linux-arm64.txz