upgrade prop-types to an MIT-licensed version

[peterschretlen]

Summary

Update the version of prop-types we use. The version of prop-types@15.5.8 used in Kibana has a BSD-3 + PATENTS license. The clauses in the patents file can raise concerns with organizations and using the MIT licensed version 15.6.0 or later is preferred.

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[peterschretlen]

retest.
CI failure looked like it was due to offline node

java.io.IOException: Cannot retrieve the node's workspace for hudson.matrix.MatrixProject@3eae0d80[elastic+kibana+pull-request]. Most probably the node is offline

trying again...

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[peterschretlen]

Manually reviewed the changes between 15.5.8 and 15.6.0, no concerns:

v15.6.0

Compare Source

• Switch from BSD + Patents to MIT license
• Add PropTypes.exact, like PropTypes.shape but warns on extra object keys. (@​thejameskyle and @​aweary in #​41 and #​87)

v15.5.10

Compare Source

• Fix a false positive warning when using a production UMD build of a third-party library with a DEV version of React. (@​gaearon in #​50)

v15.5.9

Compare Source

• Add loose-envify Browserify transform for users who don't envify globally. (@​mridgway in #​45)