re-enable Pharo4 testing as well

Johan Brichau · Johan Brichau · commit a439867f3d2a · 2018-07-26T09:23:03.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -6,6 +6,7 @@ smalltalk:
   - Pharo64-6.1
   - Pharo-6.1
   - Pharo-5.0
+  - Pharo-4.0
   - Pharo-3.0
   - Squeak-trunk
   - Squeak-5.1
