Update Docker image to Alpine 3.6

ChangeLog

@@ -3,7 +3,7 @@ Version 1.0.44 (unreleased)
 
 Improvements:
 
-* Update Docker image to Alpine Linux 3.5
+* Update Docker image to Alpine Linux 3.6
 * Add the possibility to pass API token as environment variable for Docker container
 * Add wildcard search for task reference field
 * Improve automated action TaskAssignColorOnDueDate to update task only when necessary

composer.lock

@@ -1688,23 +1688,23 @@
         },
         {
             "name": "sebastian/diff",
-            "version": "1.4.1",
+            "version": "1.4.3",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/diff.git",
-                "reference": "13edfd8706462032c2f52b4b862974dd46b71c9e"
+                "reference": "7f066a26a962dbe58ddea9f72a4e82874a3975a4"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/diff/zipball/13edfd8706462032c2f52b4b862974dd46b71c9e",
+                "url": "https://api.github.com/repos/sebastianbergmann/diff/zipball/7f066a26a962dbe58ddea9f72a4e82874a3975a4",
-                "reference": "13edfd8706462032c2f52b4b862974dd46b71c9e",
+                "reference": "7f066a26a962dbe58ddea9f72a4e82874a3975a4",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.3"
+                "php": "^5.3.3 || ^7.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.8"
+                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.0"
             },
             "type": "library",
             "extra": {
@@ -1736,7 +1736,7 @@
             "keywords": [
                 "diff"
             ],
-            "time": "2015-12-08 07:14:41"
+            "time": "2017-05-22 07:24:03"
         },
         {
             "name": "sebastian/environment",