Dropped PHP 5.6 and PHP 7.0

Updated packages in composer to latest stable version and PHP requirements
changed to PHP ^7.1
Updated suggestion in composer.

Author: michalbundyra

.travis.yml

@@ -23,34 +23,16 @@ env:
 
 matrix:
   include:
-    - php: 5.6
-      env:
-        - DEPS=lowest
-    - php: 5.6
-      env:
-        - DEPS=locked
-        - TEST_COVERAGE=true
-        - DEPLOY_DOCS="$(if [[ $TRAVIS_BRANCH == 'master' && $TRAVIS_PULL_REQUEST == 'false' ]]; then echo -n 'true' ; else echo -n 'false' ; fi)"
-        - PATH="$HOME/.local/bin:$PATH"
-    - php: 5.6
-      env:
-        - DEPS=latest
-    - php: 7
-      env:
-        - DEPS=lowest
-    - php: 7
-      env:
-        - DEPS=locked
-        - CS_CHECK=true
-    - php: 7
-      env:
-        - DEPS=latest
     - php: 7.1
       env:
         - DEPS=lowest
     - php: 7.1
       env:
         - DEPS=locked
+        - DEPLOY_DOCS="$(if [[ $TRAVIS_BRANCH == 'master' && $TRAVIS_PULL_REQUEST == 'false' ]]; then echo -n 'true' ; else echo -n 'false' ; fi)"
+        - PATH="$HOME/.local/bin:$PATH"
+        - TEST_COVERAGE=true
+        - CHECK_CS=true
     - php: 7.1
       env:
         - DEPS=latest

composer.json

@@ -14,21 +14,21 @@
         }
     },
     "require": {
-        "php": "^5.6 || ^7.0",
+        "php": "^7.1",
         "container-interop/container-interop": "^1.2",
         "psr/container": "^1.0",
         "zendframework/zend-stdlib": "^3.1"
     },
     "require-dev": {
-        "ocramius/proxy-manager": "^1.0 || ^2.0",
-        "phpbench/phpbench": "^0.10.0",
-        "phpunit/phpunit": "^5.7 || ^6.0.6",
-        "mikey179/vfsStream": "^1.6",
+        "mikey179/vfsStream": "^1.6.4",
+        "ocramius/proxy-manager": "^2.1.1",
+        "phpbench/phpbench": "^0.13.0",
+        "phpunit/phpunit": "^6.2.3",
         "zendframework/zend-coding-standard": "~1.0.0"
     },
     "suggest": {
-        "ocramius/proxy-manager": "ProxyManager 1.* to handle lazy initialization of services",
-        "zendframework/zend-stdlib": "zend-stdlib ^2.5 if you wish to use the MergeReplaceKey or MergeRemoveKey features in Config instances"
+        "ocramius/proxy-manager": "ProxyManager ^2.1.1 to handle lazy initialization of services",
+        "zendframework/zend-stdlib": "zend-stdlib ^2.7.7 | ^3.1 if you wish to use the MergeReplaceKey or MergeRemoveKey features in Config instances"
     },
     "minimum-stability": "dev",
     "prefer-stable": true,