enhance: Add comprehensive .gitignore for deb-mock project

- Add mock-specific build artifacts (chroot/, mock-*, mockroot/)
- Include package build files (*.deb, *.changes, *.buildinfo)
- Add development tools (.coverage, .pytest_cache, .tox)
- Include system files (.DS_Store, Thumbs.db, ._*)
- Add temporary and backup files (*.tmp, *.bak, *.backup)
- Include local configuration overrides (config.local.yaml, .env.local)
- Add test artifacts and documentation builds
- Comprehensive coverage for Python build system project

This ensures build artifacts, chroot environments, and development
tools are properly ignored in version control.

docs/Release-Notes-1.4.19.md

@@ -0,0 +1,17 @@
+---
+layout: default
+title: Release Notes 1.4.19
+---
+
+Released on 2019-09-10.
+
+## Mock bugfixes:
+
+ * Biggest reason for this release have been regression that results are owned by root user instead of unpriv user [[GH#322]](https://github.com/rpm-software-management/mock/issues/322)
+ * Previously resultdir variable in config has not been documented. This is now fixed.
+
+Following contributors contributed to this release:
+
+* Silvie Chlupová
+
+Thank you.