Updated CI and Composer

Updated the composer requirement to use ext-trader >= 0.4.1. This is the minimum version that is compatible with the test suite. There was a bug in 0.4.0.

Added PHP 7.3 and 7.4 to the Travis and GitLab CI suites.

Author: jb-lopez

.gitlab-ci.yml

@@ -27,3 +27,9 @@ test:7.1:
 test:7.2:
   image: php:7.2
   extends: .tests
+test:7.3:
+  image: php:7.3
+  extends: .tests
+test:7.4:
+  image: php:7.4
+  extends: .tests

.travis.yml

@@ -8,6 +8,8 @@ php:
   - 7.0
   - 7.1
   - 7.2
+  - 7.3
+  - 7.4
 
 before_script:
   - sudo apt-get update > /dev/null

composer.json

@@ -18,7 +18,7 @@
   "require-dev": {
     "phpunit/phpunit": "~6.0",
     "phpmetrics/phpmetrics": "~2.3",
-    "ext-trader": "~0.4",
+    "ext-trader": ">=0.4.1",
     "codacy/coverage": "~1.4"
   },
   "autoload": {