python3Packages.update_checker: disable py2

```
builder for '/nix/store/2qwl0rkdm2gx2byhpmw7lxyg5rprwqqk-python2.7-update_checker-0.18.0.drv' failed with exit code 1; last 10 log lines:
  no configure script, doing nothing
  building
  Executing setuptoolsBuildPhase
  Traceback (most recent call last):
    File "nix_run_setup", line 8, in <module>
      exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\\r\\n', '\\n'), __file__, 'exec'))
    File "setup.py", line 9
      with open(f"{MODULE_NAME}.py") as fp:
                                  ^
  SyntaxError: invalid syntax
```

1 files changed, 3 insertions, 1 deletions

diff --git a/pkgs/development/python-modules/update_checker/default.nix b/pkgs/development/python-modules/update_checker/default.nix
index fd3d0b02b630c..6779a50e2c47e 100644
--- a/pkgs/development/python-modules/update_checker/default.nix
+++ b/pkgs/development/python-modules/update_checker/default.nix
@@ -1,8 +1,10 @@
-{ stdenv, buildPythonPackage, fetchPypi, requests}:
+{ stdenv, buildPythonPackage, fetchPypi, requests, isPy27
+}:
 
 buildPythonPackage rec {
   pname = "update_checker";
   version = "0.18.0";
+  disabled = isPy27;
 
   src = fetchPypi {
     inherit pname version;