Follow-up: Implement storage2 trait derive proc. macros (#399)

* [core/derive] implement SpreadLayout and PackedLayout derives

* [core/derive] no longer is no_std (not useful)

Also simplified its dependencies a bit.

* [core/derive] apply rustfmt

* [core/derive] fix clippy warning
16 jobs for master in 6 minutes and 50 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Check
passed #520777
linux-docker
check-std

00:01:52

passed #520778
linux-docker
check-wasm

00:01:56

 
  Workspace
passed #520779
linux-docker
build-std

00:01:58

passed #520780
linux-docker
build-wasm

00:02:22

passed #520783
linux-docker
clippy-std

00:01:35

failed #520784
linux-docker
clippy-wasm

00:00:36

passed #520782
linux-docker
codecov

00:04:56

passed #520785
linux-docker
fmt

00:00:36

passed #520781
linux-docker
test

00:02:54

 
  Examples
passed #520788
linux-docker
examples-clippy-std

00:01:36

skipped #520789
linux-docker
examples-clippy-wasm
skipped #520790
linux-docker
examples-contract-build
skipped #520787
linux-docker
examples-fmt
passed #520791
linux-docker
examples-generate-metadata

00:01:43

passed #520786
linux-docker
examples-test

00:01:51

 
  Publish
skipped #520792
linux-docker
publish-docs
 
Name Stage Failure
failed
clippy-wasm Workspace
error: could not compile `ink_alloc`.

Caused by:
process didn't exit successfully: `/usr/local/rustup/toolchains/nightly-2020-05-14-x86_64-unknown-linux-gnu/bin/clippy-driver rustc --crate-name ink_alloc --edition=2018 alloc/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata -Cembed-bitcode=no -C debuginfo=2 -C metadata=df46c1e1c856e644 -C extra-filename=-df46c1e1c856e644 --out-dir /ci-cache/ink/targets/master/clippy-wasm/wasm32-unknown-unknown/debug/deps --target wasm32-unknown-unknown -C incremental=/ci-cache/ink/targets/master/clippy-wasm/wasm32-unknown-unknown/debug/incremental -L dependency=/ci-cache/ink/targets/master/clippy-wasm/wasm32-unknown-unknown/debug/deps -L dependency=/ci-cache/ink/targets/master/clippy-wasm/debug/deps --extern wee_alloc=/ci-cache/ink/targets/master/clippy-wasm/wasm32-unknown-unknown/debug/deps/libwee_alloc-1754bd530752b402.rmeta` (exit code: 101)
warning: build failed, waiting for other jobs to finish...
error: build failed
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1