Update dependency babel-plugin-istanbul to v5.2.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
babel-plugin-istanbul	devDependencies	minor	5.1.4 -> 5.2.0

---

Release Notes

istanbuljs/babel-plugin-istanbul

### [`v5.2.0`](https://togithub.com/istanbuljs/babel-plugin-istanbul/blob/master/CHANGELOG.md#​520httpsgithubcomistanbuljsbabel-plugin-istanbulcomparev514v520-2019-07-18) [Compare Source](https://togithub.com/istanbuljs/babel-plugin-istanbul/compare/v5.1.4...v5.2.0) ##### Bug Fixes - Print explicit error if use with babel 6 is attempted ([#​207](https://togithub.com/istanbuljs/babel-plugin-istanbul/issues/207)) ([a12cf16](https://togithub.com/istanbuljs/babel-plugin-istanbul/commit/a12cf16)) ##### Features - Support turning off node_modules default exclude via flag ([#​172](https://togithub.com/istanbuljs/babel-plugin-istanbul/issues/172)) ([a314f06](https://togithub.com/istanbuljs/babel-plugin-istanbul/commit/a314f06))

---

Renovate configuration

:date: Schedule: "every weekend" (UTC).

:vertical_traffic_light: Automerge: Enabled.

:recycle: Rebasing: Whenever PR is stale, or if you modify the PR title to begin with "rebase!".

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by Renovate Bot. View repository job log here.