Release version 2.6.0

[notgull]

• Add level and edge triggered modes to the poller (Add level and edge triggered modes to the poller #59)
• Support tvOS and watchOS (Support tvOS and watchOS #60)
• Prevent large timeouts from causing panics on certain backends (bugfix: Prevent large timeouts from causing panics #71)
• For certain BSDs, use EVFILT_USER to wake up the poller instead of a pipe (m: Use EVFILT_USER instead of a self-pipe on kqueue where supported #73)
• For Solaris/illumos, use port_send to wake up the poller instead of a pipe (m: Use port_send for event ports instead of a pipe #74)
• Update windows_sys from 0.42 to 0.45 (Update windows-sys requirement from 0.42 to 0.45 #80)
• Expose other kqueue filter types (feat: Expose other kqueue filters #83)
• Replace the Windows backend with a hand-written version, rather than bringing in a C dependency (m(windows): Reimplement Wepoll in Rust #88)