Improve flexibility of the artifact building workflow #46
Description
Currently the workflow hardcodes the riscv-gnu-toolchain tag to use. It also hardcodes the ISA and ABI but it is less likely to change.
The dockerfile also hardcodes the artifact to use.
Both hardcode the ubuntu version.
I'm wondering whether we can do something to not have to update both each time we want to update the artifact or the ubuntu version.