chore: use openssl only on non-Windows platforms

[weihanglo]

On Windows, the system-provided Schannel will be used instead.

See

• Make cargo a workspace rust#109133 (comment)

• cargo/README.md

  Lines 38 to 49 in 39116cc

  	* OpenSSL — Only needed on Unix-like systems and only if the `vendored-openssl` Cargo feature is not used.
  	This requires the development headers, which can be obtained from the `libssl-dev` package on Ubuntu or `openssl-devel` with apk or yum or the `openssl` package from Homebrew on macOS.
  	If using the `vendored-openssl` Cargo feature, then a static copy of OpenSSL will be built from source instead of using the system OpenSSL.
  	This may require additional tools such as `perl` and `make`.
  	On macOS, common installation directories from Homebrew, MacPorts, or pkgsrc will be checked. Otherwise it will fall back to `pkg-config`.
  	On Windows, the system-provided Schannel will be used instead.
  	LibreSSL is also supported.

[rustbot]

r? @ehuss

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[ehuss]

Thanks!

@bors r+

[bors]

📌 Commit a0bb59c has been approved by ehuss

It is now in the queue for this repository.

[bors]

⌛ Testing commit a0bb59c with merge d0a4cbc...

[bors]

☀️ Test successful - checks-actions
Approved by: ehuss
Pushing d0a4cbc to master...