remove pgproto dir after moving pgproto to picodata

pgproto/.cargo/config.toml

pgproto/.gitignore

pgproto/.gitlab-ci.yml

pgproto/Cargo.lock

pgproto/Cargo.toml

pgproto/Dockerfile.ci

pgproto/Pipfile

pgproto/Pipfile.lock

pgproto/README.md

pgproto/cmake/FindMsgPuck.cmake

pgproto/cmake/utils.cmake

pgproto/examples/demo.lua

pgproto/examples/magic.sh

pgproto/pytest.ini

pgproto/setup.cfg

pgproto/test-requirements.txt

pgproto/test/CMakeLists.txt

pgproto/test/conftest.py

pgproto/test/pgdata/gen_certs.sh