Support no_std

[koushiro]

• Add std feature and default feature
• Support no_std
• Update CI for no_std check

Close #286
Close #327

Signed-off-by: koushiro [email protected]

[coveralls]

Pull Request Test Coverage Report for Build 1149867009

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 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 90.107%

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Totals
Change from base Build 1149764896:	0.0%
Covered Lines:	5492
Relevant Lines:	6095

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💛 - Coveralls

[koushiro]

@Dandandan PTAL

[alamb]

Thank you @koushiro !

I reviewed the code and the output of the new CI check https://github.com/sqlparser-rs/sqlparser-rs/pull/332/checks?check_run_id=3379689095 and it looks good to me

cc @Dandandan let me know if you have any issues with merging this PR

[alamb]

Is the change to resolver v2 needed for this change, or is it a nice to have / drive by cleanup?

reference https://doc.rust-lang.org/cargo/reference/resolver.html#feature-resolver-version-2

[koushiro]

Actually, it was added to pass CI 'compile-no-std' check

Because the dev-dependency 'simple_logger' introduces the std feature of log, if resolver=2 is not used, libstd will be implicitly introduced in the CI 'compile-no-std'