Test support for all newer versions of phpseclib

It seems only 2.0.8 is broken

.travis.yml

@@ -9,11 +9,18 @@ php:
 dist: trusty
 
 env:
+  - PHPSECLIB='^2.0 !=2.0.8'
   - PHPSECLIB="2.0.0"
   - PHPSECLIB="2.0.1"
   - PHPSECLIB="2.0.2"
   - PHPSECLIB="2.0.3"
   - PHPSECLIB="2.0.4"
+  - PHPSECLIB="2.0.5"
+  - PHPSECLIB="2.0.6"
+  - PHPSECLIB="2.0.7"
+  - PHPSECLIB="2.0.9"
+  - PHPSECLIB="2.0.10"
+  - PHPSECLIB="2.0.11"
 
 matrix:
   allow_failures:

composer.json

@@ -13,10 +13,10 @@
     }
   ],
   "require": {
-    "phpseclib/phpseclib": ">=2.0.0 <=2.0.4"
+    "phpseclib/phpseclib": "^2.0 !=2.0.8"
   },
   "require-dev": {
-    "phpunit/phpunit": "~5.0"
+    "phpunit/phpunit": "^5.0"
   },
   "suggest": {
     "ext-mcrypt": "required if you use encryption cast5"