chore: update changelog [skip ci]

Author: adhocore

CHANGELOG.md

@@ -0,0 +1,7 @@
+## [v0.0.5] 2018-08-15 10:08:16 UTC
+
+- [6fccf54](https://github.com/adhocore/php-cron-expr/commit/6fccf54) test(validator): instep changes
+- [93d2f7f](https://github.com/adhocore/php-cron-expr/commit/93d2f7f) fix(validator): inStep when start+step>end | closes #12
+- [895eade](https://github.com/adhocore/php-cron-expr/commit/895eade) docs: update readme
+- [bc65912](https://github.com/adhocore/php-cron-expr/commit/bc65912) docs: fix badge
+