Update instructions and CI for cross-compilation on Ubuntu 22.
Note that for the dockerfile, we use egrep -L which has changed and does
not exit with code 0 on no match. Instead, use -vqz to invert return
code (0 if nothing found, otherwise 1).

Tsung Yu Chan authored 1 year ago and Robert Schmidt committed 1 year ago

  can compile the target ldpc_generators and generate_T with cross-compiler