Don't commit composer.lock

This project is not an end-user project - it is far more likely to be a dependency of something else, so allow some flexibility so it can play nice with other dependencies in someone's project.

See https://andreas.heigl.org/2016/05/29/to-commit-composer-lock-or-not/

Author: GaryJones

.gitignore

@@ -1,5 +1,2 @@
-util/
-mybuild
-mytest
-myrun
+/composer.lock
 /vendor/