build: nix version is now pinned to version.txt.

Makefile

@@ -2,7 +2,7 @@
 # Builds release artifacts for GitHub releases
 
 APP_NAME := envr
-VERSION := $(shell grep 'version = ' flake.nix | head -1 | sed 's/.*version = "\(.*\)";/\1/')
+VERSION := $(file < version.txt)
 BUILD_DIR := builds
 
 # Binary names

flake.nix

@@ -66,7 +66,7 @@
 
           packages.default = pkgs.stdenv.mkDerivation rec {
             pname = "envr";
-            version = "0.3.0";
+            version = nixpkgs.lib.trim (builtins.readFile ./version.txt);
             src = ./.;
 
             nativeBuildInputs = [