Adopt new configure --dev convention

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

.travis.yml

@@ -15,7 +15,7 @@ python:
   - "3.8"
 
 # Scripts to run at install stage
-install: ./configure
+install: ./configure --dev
 
 # Scripts to run at script stage
 script: tmp/bin/pytest