cargo(deps): update nix requirement from 0.18 to 0.20

[dependabot[bot]]

Updates the requirements on nix to permit the latest version.

Changelog

Sourced from nix's changelog.

[0.20.0] - 20 February 2021

Added

• Added a passwd field to Group (#1338)
• Added mremap (#1306)
• Added personality (#1331)
• Added limited Fuchsia support (#1285)
• Added getpeereid (#1342)
• Implemented IntoIterator for Dir (#1333).

Changed

• Minimum supported Rust version is now 1.40.0. (#1356)
• i686-apple-darwin has been demoted to Tier 2 support, because it's deprecated by Xcode. (#1350)
• Fixed calling recvfrom on an AddrFamily::Packet socket (#1344)

Fixed

• TimerFd now closes the underlying fd on drop. (#1381)
• Define *_MAGIC filesystem constants on Linux s390x (#1372)
• mqueue, sysinfo, timespec, statfs, test_ptrace_syscall() on x32 (#1366)

Removed

• Dir, SignalFd, and PtyMaster are no longer Clone. (#1382)
• Removed SockLevel, which hasn't been used for a few years (#1362)
• Removed both Copy and Clone from TimerFd. (#1381)

[0.19.1] - 28 November 2020

Fixed

• Fixed bugs in recvmmsg. (#1341)

[0.19.0] - 6 October 2020

Added

• Added Netlink protocol families to the SockProtocol enum (#1289)
• Added clock_gettime, clock_settime, clock_getres, clock_getcpuclockid functions and ClockId struct. (#1281)

... (truncated)

Commits

• See full diff in compare view

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[dependabot[bot]]

Superseded by #20.