Switch to Zig 0.11.0 as default

[alexrp]

https://github.com/ziglang/zig/milestone/17

[alexrp]

With #45 closed in favor of this issue, this is now blocked on or hindered by the following:

• win-x86 packaging is currently disabled due to an upstream issue zig-toolsets#15 (not a hard blocker; we can temporarily regress win-x86 support)
  • Linking to libc for i386-windows-gnu target fails (regression) ziglang/zig#12886
• zig cc -target <arch>-windows-gnu produces a large amount of warnings ziglang/zig#13384
• -Wdeprecated-non-prototype warning in musl's dlstart.c with zig cc main.c -target aarch64-linux-musl ziglang/zig#13385
• llvm11: clang error when building c++ hello world on arm-linux-musleabi -mcpu=generic+v6kz (__libcpp_signed_lock_free) ziglang/zig#6573 (remove linux-musl-arm from default RuntimeIdentifiers?)