"Fix egg on dependency links [SKIP CI]."

.drone.yml

@@ -41,4 +41,10 @@ matrix:
           DATABASE: sqlite
         - IMAGE: python:3.7
           TOXENV: py37
+          DATABASE: postgresql
+        - IMAGE: python:3.8
+          TOXENV: py38
+          DATABASE: sqlite
+        - IMAGE: python:3.8
+          TOXENV: py38
           DATABASE: postgresql

tox.ini

@@ -1,10 +1,10 @@
 [tox]
-envlist = {py36,py37}-{sqlite,postgresql},pypy3-{sqlite,postgresql}
+envlist = {py36,py37,py38}-{sqlite,postgresql},pypy3-{sqlite,postgresql}
 
 [testenv]
 commands = {envpython} setup.py test
 deps =
-    {py36,py37}-postgresql: psycopg2 >= 2.5
+    {py36,py37,py38}-postgresql: psycopg2 >= 2.5
     pypy3-postgresql: psycopg2cffi >= 2.5
     {py36}-sqlite: sqlitebck
 setenv =