Use psycopg2 2.8 since < 2.8 prevents Python 3.8 support

Yuanfang Chen · Yuanfang Chen · commit 5868906e8da7 · 2020-01-27T12:16:22.000-08:00
psycopg/psycopg2#854
diff --git a/requirements.server.txt b/requirements.server.txt
@@ -1,6 +1,6 @@
 # These requirements are what you would install on a production server.
 -r requirements.client.txt
-psycopg2==2.7
+psycopg2==2.8
 # Flask 0.11 does not work yet.
 gunicorn==18.0
 progressbar2
