Merge pull request #152 from Mic92/release-2.2.0

release 2.2.0

add version tracking and release script

The derivation had no version, making it hard to tell which build a user
is running when debugging issues like #135. Add version.txt as the
single source of truth, referenced by default.nix via lib.fileContents.

The release script is adopted from nixpkgs-review to automate bumping
version.txt, tagging, and creating a GitHub draft release.

fix vm script invocation

this was broken by the commit introducing gcroots

Merge pull request #76 from ShamrockLee/bin-nix-run

bin/nixos-shell: use `nix run` to run; flake.nix: use `packages.<system>.default`

Merge pull request #58 from tomeon/support-extendModules

Support `extendModules` for injecting nixos-shell's options and config modules

Merge pull request #48 from welteki/flake-modules

Support flake modules

Fixes compat with nixpkgs

also fixes fish shell usage

Merge pull request #27 from Mic92/ci

passthru most common nix options to builder