statically linked binaries for Xifra the Build Breaker

[sukoneck]

use musl and cross to build statically linked bin in release pipeline.

# require openssl vendored in Config.toml
[dependencies]
openssl = { version = "0.10", features = ["vendored"], optional = false }

# target musl rather than gnu
- target: x86_64-unknown-linux-musl

# build with cross rather than cargo
run: cross build --release --target ${{ matrix.configs.target }}

[sukoneck]

merged in #15