PyWinpty release v2.0.6

Minor pywinpty release that brings support with the latest winpty-rs version, as well other dependencies.

What's Changed

• Test if closed in terminate tests by @blink1073 in #228
• Bump pyo3 from 0.16.0 to 0.16.1 by @dependabot in #229
• Bump pyo3 from 0.16.1 to 0.16.2 by @dependabot in #233
• Bump syn from 1.0.86 to 1.0.89 by @dependabot in #236
• Bump libc from 0.2.119 to 0.2.121 by @dependabot in #238
• PR: Update dependencies to latest versions by @andfoy in #252

Full Changelog: v2.0.5...v2.0.6