Switch code coverage to Tarpaulin

[zbraniecki]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 7f6f865efce7c61f38e0a74b5883d977a6218e77-PR-184

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 141 unchanged lines in 22 files lost coverage.
• Overall coverage decreased (-7.9%) to 83.218%

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Files with Coverage Reduction	New Missed Lines	%
components/data-provider-json/src/lib.rs	1	95.45%
components/locale/src/subtags/script.rs	1	88.24%
components/locale/src/subtags/variant.rs	1	90.91%
components/locale/src/subtags/region.rs	2	91.3%
components/locale/src/extensions/mod.rs	3	90.63%
components/locale/src/serde/langid.rs	3	83.33%
components/locale/src/langid.rs	5	78.26%
components/uniset/src/uniset.rs	5	95.76%
components/locale/src/extensions/private/key.rs	6	53.85%
components/locale/src/extensions/private/mod.rs	6	66.67%

Totals
Change from base Build 1e3b00ea3b0456993de8f1f2ee0b4cbfb90ddc7f:	-7.9%
Covered Lines:	843
Relevant Lines:	1013

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💛 - Coveralls

[zbraniecki]

It was my attempt to see if switching to tarpaulin will give better coverage than grcov, but it seems that it has even more false positives.

I like tarpaulin because you can easily launch it locally with cargo tarpaulin -v and you can set #[cfg(not(tarpaulin))] to ignore a given file.
I'll keep this PR closed and re-try in some time.