Remove poetry2nix-release tool

I'm now always fully relying on Github Actions for testing pre-release.
This tool isn't helpful and makes the development shell larger.

shell.nix

@@ -16,7 +16,6 @@ pkgs.mkShell {
     tools.env
     tools.py2-astparse
     tools.flamegraph
-    tools.release
     pkgs.nixpkgs-fmt
     pkgs.poetry
     pkgs.niv

tools/default.nix

@@ -11,43 +11,6 @@ let
 in
 {
 
-  release =
-    let
-      pythonEnv = pkgs.python3.withPackages (
-        ps: [
-          ps.pythonix
-        ]
-      );
-    in
-    pkgs.writeScriptBin "poetry2nix-release" ''
-      #!${pythonEnv.interpreter}
-      import subprocess
-      import argparse
-      import nix
-      import sys
-
-      if __name__ == '__main__':
-          tag_latest = subprocess.run(['git', 'describe', '--abbrev=0'], stdout=subprocess.PIPE, check=True).stdout.decode().strip()
-          version_latest = nix.eval('(import ${srcPath} {}).version')
-
-          if tag_latest == version_latest:
-            sys.stderr.write('Version number not bumped in default.nix\n')
-            sys.stderr.flush()
-            exit(1)
-
-          p = subprocess.run(['git', 'status', '--short'], stdout=subprocess.PIPE)
-          if p.stdout.decode().strip() != "":
-            sys.stderr.write('Git tree is dirty\n')
-            sys.stderr.flush()
-            exit(1)
-
-          subprocess.run(['nix-build', '--no-out-link', '${srcPath + "/tests"}'], check=True)
-          subprocess.run(['${srcPath + "/check-fmt"}'], check=True)
-
-          p = subprocess.run(['git', 'tag', '-a', version_latest])
-          exit(p.returncode)
-    '';
-
   flamegraph =
     let
       runtimeDeps = lib.makeBinPath [