Bump chokidar & juice to resolve a security vulnerability

[schmod]

Small PR to bump two dependencies that have transitive dependencies with vulnerabilities (as found by snyk):

✗ High severity vulnerability found in set-value
  Description: Prototype Pollution
  Info: https://snyk.io/vuln/SNYK-JS-SETVALUE-450213
  Introduced through: mjml@4.4.0-beta.2
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > braces@2.3.2 > snapdragon@0.8.2 > base@0.11.2 > cache-base@1.0.1 > set-value@2.0.0
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > readdirp@2.2.1 > micromatch@3.1.10 > snapdragon@0.8.2 > base@0.11.2 > cache-base@1.0.1 > set-value@2.0.0
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > anymatch@2.0.0 > micromatch@3.1.10 > snapdragon@0.8.2 > base@0.11.2 > cache-base@1.0.1 > set-value@2.0.0
  and 19 more...

✗ High severity vulnerability found in mixin-deep
  Description: Prototype Pollution
  Info: https://snyk.io/vuln/SNYK-JS-MIXINDEEP-450212
  Introduced through: mjml@4.4.0-beta.2
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > braces@2.3.2 > snapdragon@0.8.2 > base@0.11.2 > mixin-deep@1.3.1
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > readdirp@2.2.1 > micromatch@3.1.10 > snapdragon@0.8.2 > base@0.11.2 > mixin-deep@1.3.1
  From: mjml@4.4.0-beta.2 > mjml-cli@4.4.0-beta.2 > chokidar@2.1.6 > anymatch@2.0.0 > micromatch@3.1.10 > snapdragon@0.8.2 > base@0.11.2 > mixin-deep@1.3.1
  and 8 more...

✗ High severity vulnerability found in lodash.merge
  Description: Prototype Pollution
  Info: https://snyk.io/vuln/SNYK-JS-LODASHMERGE-173732
  Introduced through: mjml@4.4.0-beta.2
  From: mjml@4.4.0-beta.2 > mjml-core@4.4.0-beta.2 > juice@4.3.2 > cheerio@0.22.0 > lodash.merge@4.6.1
  From: mjml@4.4.0-beta.2 > mjml-head-title@4.4.0-beta.2 > mjml-core@4.4.0-beta.2 > juice@4.3.2 > cheerio@0.22.0 > lodash.merge@4.6.1
  From: mjml@4.4.0-beta.2 > mjml-button@4.4.0-beta.2 > mjml-core@4.4.0-beta.2 > juice@4.3.2 > cheerio@0.22.0 > lodash.merge@4.6.1
  and 26 more...

---

• Chokidar changelog -- v3 drops support for Node 6 and below (which is itself unsupported)
• Juice changelog -- No breaking changes were documented in v5
• The lodash vulnerability (via cheerio) is still open, and is waiting for fix: prototype pollution in several npm packages lodash/lodash#4337 to appear in a release.

[iRyusa]

I'm not sure that the very light small test suite is able to provide any feedback on support to node 12 yet.

For the version bump I think we can just merge this directly cc @kmcb777

[schmod]

Yeah. I basically just listed all of the Node versions that are still within their support/maintenance window. Given that the tests currently pass, it seems like a reasonable start 🤷‍♂