[nodejs] default to stable yarn 0.27.5 (--production flag works)

[lucasts]

• update to latest yarn stable release
• bring back --production flag

yarn>=0.20 fixed --production flag which would not install required packages.

yarn solution and explanation on what triggered the problem: yarnpkg/yarn#2537

[lucasts]

@raphamorim @rwillrich what do you think?

[lucasts]

closes #38 as well

[rwillrich]

@lucasts we could use a SemVer compatible version range, like ^0.25.0, what do you think?

[raphamorim]

Nice @lucasts

@rwillrich: This is a good suggest, but I like to recommend other version for SemVer approach: ^0.27.0

Because updates/fixes on issues about race condition and environment checker when script is running (more)

[lucasts]

@raphamorim @rwillrich interesting But I personally do not trust yarn releases on that level.

From a tsuru standpoint I think it is better to have a fixed default version. users can specify a SemVer compatible string in their package.json if needed.

[raphamorim]

good point @lucasts,
make sense it to me 👍

If yarn breaks in any bad minor future version, we all break together 😆

[cezarsa]

Manually rebased/merged in 89314ac. I also bumped the default version to 1.3.2 as yarn should be stable now that we're past 1.0.