Update the version-fixing patch for Nix

nix/setup.cfg.patch

@@ -2,11 +2,11 @@ diff --git a/setup.cfg b/setup.cfg
 index dfc49607..822ea8dd 100644
 --- a/setup.cfg
 +++ b/setup.cfg
-@@ -40,7 +40,7 @@ install_requires =
+@@ -40,5 +40,5 @@ install_requires =
      # incompatible with Tahoe-LAFS'.  So duplicate them here (the ones that
      # have been observed to cause problems).
      Twisted[tls,conch]>=18.4.0
--    tahoe-lafs==1.14.0
+-    tahoe-lafs >=1.14, <1.17, !=1.15.*
 +    tahoe-lafs
      treq