Update syn, quote and proc-macro2

[hcpl]

No description provided.

[nrc]

Looks like nightly tests are failing. Do you know what is happening there?

[hcpl]

This is because each of these commands:

derive-new/.travis.yml

Lines 6 to 9 in f944f10

	- rust: nightly
	script:
	- cargo test
	- cargo test --manifest-path testcrate/Cargo.toml

creates its own target/debug/deps/libderive_new-${hash}.so with a unique hash which confuses compiletest_rs since it doesn't know how to tell which one is the right one.

[nrc]

Thanks for the PR!

[hcpl]

I just tried the script below which resolved this problem for me:

#!/bin/sh
cargo +nightly test
rm target/debug/deps/libderive_new-*.so
cargo +nightly test --manifest-path testcrate/Cargo.toml

I'll try to adapt this for .travis.yml in the next PR.