Issue

Previously working Gitlab configuration stopped working at all, hooks are sent by gitlab but they're not triggering the actual job. After investigation I've found out that gitlab changed Hook headers (without documenting it) thus breaking the plugin's ability to trigger jobs using hooks.

Context

• Gitlab plugin version: 1.4.7
• Gitlab version: 9.5.0.RC8
• Jenkins version: 2.60.2
• Job type: Pipeline