Changed version to v1.5.0-dev after v1.4.0 released

composer.json

 {
   "name": "cesnet/simplesamlphp-module-proxystatistics",
   "description": "A SimpleSAMLPHP module for statistics",
-  "version": "1.4.0-dev",
+  "version": "1.5.0-dev",
   "type": "simplesamlphp-module",
   "keywords": ["statistics","simplesamlphp"],
   "license": "BSD-2-Clause",