Remove test_fstrings_allowed.

This test was useful when Python 2.7 or 3.5 was supported, but they no longer are.

tests/test_scripts.py

@@ -93,22 +93,6 @@ def test_index_url(self):
         reqs = scripts.DepsReader(script).read()
         assert reqs.index_url == 'https://my.private.index/'
 
-    def test_fstrings_allowed(self):
-        """
-        It should be possible to read dependencies from a script
-        with f-strings on all Pythons.
-        """
-        script = DALS(
-            """
-            # coding: future_fstrings
-            __requires__ = ['foo']
-            f'boo'
-            f'coo'
-            """
-        )
-        reqs = scripts.DepsReader(script).read()
-        assert reqs == ['foo']
-
     def test_comment_style(self):
         script = textwrap.dedent(
             """