[Snyk] Fix for 26 vulnerabilities

[jamiecool]

Snyk has created this PR to fix 26 vulnerabilities in the yarn dependencies of this project.

Snyk changed the following file(s):

• __tests__/fixtures/add/install-should-cleanup-when-package-json-changed-3/package.json
• __tests__/fixtures/add/install-should-cleanup-when-package-json-changed-3/yarn.lock

Note for zero-installs users

If you are using the Yarn feature zero-installs that was introduced in Yarn V2, note that this PR does not update the .yarn/cache/ directory meaning this code cannot be pulled and immediately developed on as one would expect for a zero-install project - you will need to run yarn to update the contents of the ./yarn/cache directory.
If you are not using zero-install you can ignore this as your flow should likely be unchanged.

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Prototype Pollution SNYK-JS-LODASH-567746	731
	Remote Memory Exposure SNYK-JS-BL-608877	706
	Prototype Pollution SNYK-JS-LODASH-6139239	696
	Regular Expression Denial of Service (ReDoS) SNYK-JS-SEMVER-3247795	696
	Prototype Pollution SNYK-JS-INI-1048974	686
	Prototype Pollution SNYK-JS-LODASH-450202	686
	Prototype Pollution SNYK-JS-LODASH-608086	686
	Prototype Pollution SNYK-JS-LODASH-73638	686
	Prototype Pollution npm:deep-extend:20180409	686
	Code Injection SNYK-JS-LODASH-1040724	681
	Regular Expression Denial of Service (ReDoS) npm:is-url:20180319	676
	Prototype Pollution npm:lodash:20180130	636
	Arbitrary Code Execution npm:ejs:20161128	619
	Prototype Pollution SNYK-JS-MINIMIST-559764	601
	Regular Expression Denial of Service (ReDoS) npm:underscore.string:20170908	589
	Regular Expression Denial of Service (ReDoS) SNYK-JS-HOSTEDGITINFO-1088355	586
	Regular Expression Denial of Service (ReDoS) SNYK-JS-LODASH-1018905	586
	Prototype Pollution npm:extend:20180424	579
	Regular Expression Denial of Service (ReDoS) SNYK-JS-LODASH-73639	541
	Cross-site Scripting (XSS) npm:ejs:20161130	509
	Denial of Service (DoS) npm:ejs:20161130-1	509
	Prototype Pollution SNYK-JS-MINIMIST-2429795	506
	Regular Expression Denial of Service (ReDoS) npm:debug:20170905	506
	Regular Expression Denial of Service (ReDoS) SNYK-JS-MINIMATCH-3050818	479
	Regular Expression Denial of Service (ReDoS) npm:mime:20170907	399
	Regular Expression Denial of Service (ReDoS) npm:ms:20170412	399

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• Check the changes in this PR to ensure they won't cause issues with your project.
• Max score is 1000. Note that the real score may have changed since the PR was raised.
• This PR was automatically created by Snyk using the credentials of a real user.

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