Upgrade bitcoin-abc-dev to debian bullseye

Summary: Bullseye has been stable for development for a few weeks. Upgrading provides developers with better and more up to date tooling by default.

Test Plan:

docker build -t bitcoin-abc-dev -f contrib/docker/bitcoin-abc-dev/Dockerfile
docker run -it bitcoin-abc-dev
mkdir build
cd build
cmake -GNinja ..
ninja check check-functional

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D12375