upgrade to 2.0.0-rc5 (like rococo)

[brenzi]

first, upgrade (merge, not rebase! keep our history and tags)
https://github.com/scs/substrate-api-client-test-node

then the api-client

[brenzi]

git checkout master
git pull
git checkout -b upgrade-to-v2.0.0-rc5
git fetch upstream
git merge 8f769dbd971c44f0ca6747fa1595f6e6a7e57c64

merging an upstream tag didn't work. needed to name the commit

..and resolve conflicts!

*stick to crates.io in Cargo.toml's! * upstream wants to depend on git but that's not good for us. we prefer to checkin Cargo.lock files to avoid accidental upgrades

won't build with nightly-2020-02-06-x86_64-unknown-linux-gnu. needs more recent nightly

ran into this: paritytech/substrate#6167

had to edit Cargo.lock to get rid of 2.0.0-rc6 and 0.8.0-rc6 deps

then run sed -i '/^checksum/d' Cargo.lock

[brenzi]

stuck at:
paritytech/substrate#6167 (comment)

update

fixed by

cargo update -p parity-scale-codec-derive