Update actions/cache action to v3 - autoclosed

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
actions/cache	action	major	v2 -> v3

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Release Notes

actions/cache

### [`v3`](https://togithub.com/actions/cache/compare/v2...v3) [Compare Source](https://togithub.com/actions/cache/compare/v2...v3)

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Configuration

📅 Schedule: Branch creation - "before 7am every weekday" in timezone Europe/Brussels, Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

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

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• [ ] If you want to rebase/retry this PR, click this checkbox.

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

[coveralls]

Pull Request Test Coverage Report for Build 2020080545

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 1922210134:	0.0%
Covered Lines:	1248
Relevant Lines:	1248

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 2020080545

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 1922210134:	0.0%
Covered Lines:	1248
Relevant Lines:	1248

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💛 - Coveralls