Merge ~cjwatson/launchpad:remove-futures into launchpad:master

[Colin Watson]

Remove futures requirement

This is no longer needed on Python 3.

[Jürgen Gmach (jugmac00)]

review: Approve

diff --git a/requirements/launchpad.txt b/requirements/launchpad.txt
index e15a388..a76d45e 100644
--- a/requirements/launchpad.txt
+++ b/requirements/launchpad.txt
@@ -55,7 +55,6 @@ fastimport==0.9.8
 feedparser==5.2.1
 flit-core==3.3.0
 FormEncode==1.3.1
-futures==3.3.0
 geoip2==2.9.0
 grokcore.component==3.1
 gunicorn==20.1.0
diff --git a/setup.cfg b/setup.cfg
index be574c6..72ea910 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -33,12 +33,6 @@ install_requires =
     dohq-artifactory
     feedparser
     fixtures
-    # Required for gunicorn[gthread].  We depend on it explicitly because
-    # gunicorn declares its dependency in a way that produces (and thus may
-    # cache) different wheels depending on whether it was built on Python 2
-    # or 3 while claiming that the wheels are universal.
-    # XXX cjwatson 2020-02-03: Remove this once we're on Python 3.
-    futures; python_version < "3.2"
     geoip2
     gunicorn
     importlib-resources; python_version < "3.7"