fix(ci): pin native-tls to 0.2.13 and flate2 to 1.0.35

[oleonardolima]

Description

In the latest native-tls release 0.2.14 it's bumped their MSRV version to 1.80.0.

It's not a direct dependency, however, it comes as a transitive dependency from reqwest.

Alongside that, the flate2 dependency also bumped their MSRV to 1.67.0 which also requires pinning its version to 1.0.35.

This PR pins on CI both the native-tls to 0.2.13, and flate2 to 1.0.35, and updates the instruction on README.md in order to properly build on MSRV.

Notes to the reviewers

Changelog notice

• Adds native-tls 0.2.13 to MSRV pinning step on CI.
• Adds flate2 1.0.35 to MSRV pinning step on CI.

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

[coveralls]

Pull Request Test Coverage Report for Build 13551188773

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 88.167%

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Files with Coverage Reduction	New Missed Lines	%
src/api.rs	1	53.03%

Totals
Change from base Build 12165803391:	-0.2%
Covered Lines:	1140
Relevant Lines:	1293

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💛 - Coveralls

[ValuedMammal]

ACK 84161ba