ci: trigger Docker build only on release + bump version to 1.9.1

Author: yassirkachri

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='kosty',
-    version='1.9',
+    version='1.9.1',
     author='Yassir Kachri',
     author_email='yassir@kosty.cloud',
     description='AWS Cost Optimization & Security Audit CLI Tool - Identify cost waste, security vulnerabilities, and compliance issues across 16 core AWS services',