Remove yarn, add jenkinsfile to npmignore

[sgtcoolguy]

I'm trying to get more standardized on builds, and moving back to npm 5 is good.

You can also re-use some build steps defined in the pipeline library to replace some chunks of the Jenkinsfile now.

For example the JIRA section can use this now (just keep the if guard so it doesn't happen on non-master branches):

updateJIRA('TIMOB', "windowslib ${packageVersion}", scm)

Also, I'm moving to trigger publish/tagging/JIRA updates to if the branch is explicitly 'master', rather than when it's not a PR.

So I'm changing:

def isPR = false
// ...
isPR = env.BRANCH_NAME.startsWith('PR-')
// ...
if (!isPR) {
  bat 'npm publish'
}

to:

def isMaster = false
// ...
isMaster = env.BRANCH_NAME.equals('master')
// ...
if (isMaster) {
  bat 'npm publish'
}

[ewanharris]

@sgtcoolguy Thanks, I'll update with your suggestions tomorrow, . If we're going to be using npm5 I might try and replace the npm i --global calls with npx too

[ewanharris]

@sgtcoolguy Updated to use your suggestions, didn't go with npx as the version in npm@5.2.0 seems broken on Windows, 5.3.0 works but kept with 5.2.0 to avoid causing any other repos problems.