Try conditional build with Travis

.travis.yml

@@ -6,8 +6,6 @@
 os: linux
 dist: xenial
 #dist: bionic
-# Deprecated: The key sudo has no effect anymore.
-#sudo: required
 
 language: php
 
@@ -33,10 +31,10 @@ addons:
     # We need pgloader for import mysql database into pgsql
     - pgloader
 
-php:
-- '5.6'
-- '7.4'
-- nightly
+#php:
+#- '5.6'
+#- '7.4'
+#- nightly
 
 env:
   global:
@@ -49,8 +47,6 @@ env:
   - DB=postgresql
   # See https://docs.travis-ci.com/user/languages/php/#Apache-%2B-PHP
   #- WS=apache
-  # See https://github.com/DracoBlue/travis-ci-nginx-php-fpm-test
-  #- WS=nginx
 
 jobs:
   fast_finish: true
@@ -58,24 +54,17 @@ jobs:
   - php: nightly
   # We exclude some combinations not usefull to save Travis CPU
   exclude:
-  - php: '7.0'
-    env: DB=mysql
-  - php: '7.1'
-    env: DB=mysql
-  - php: '7.2'
-    env: DB=mysql
-  - php: '7.3'
-    env: DB=mysql
-  - php: '7.0'
-    env: DB=postgresql
-  - php: '7.1'
-    env: DB=postgresql
-  - php: '7.2'
-    env: DB=postgresql
-  - php: '7.3'
-    env: DB=postgresql
   - php: nightly
     env: DB=postgresql
+  include:
+    - if: type = pull_request
+      php: '7.4'
+    - if: type = push
+      php: 
+      - '5.6'
+      - '7.4'
+    - if: type = push AND branch = develop
+      php: nightly 
 
 notifications:
   email: