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-2.5.md

@@ -0,0 +1,48 @@
+---
+layout: default
+title: Release Notes 2.5
+---
+
+Released on - 2020-09-03.
+
+## Mock 2.5 features:
+
+ * Since the introduction of `mock-configs` virtual provides, it can
+   happen that `mock-core-configs` is not actually installed.  Previously,
+   the `mock` group would be missing though on such installation because
+   it was installed by the `mock-core-configs` package.  Newly, both
+   `mock` and `mock-core-configs` depend on the new `mock-filesystem`
+   package that is responsible for installing both the `mock` system group
+   and some basic directory layout.
+
+ * Mock newly configures the DNF so it sets a custom HTTP User Agent
+   header when downloading packages.  This information can be later used
+   for better download statistics (e.g.normal end-user package downloads
+   vs. build-system downloads).
+
+ * A new [showrc plugin](https://rpm-software-management.github.io/mock//Plugin-Showrc) was added.  It puts the output of the command
+   `rpm --showrc` into a separate log file in result directory so users may
+   e.g. use this info during debugging the macro definition peculiarities.
+
+
+## Mock 2.5 bugfixes:
+
+ * Previously, when macro wasn't specified with leading `%` (see the
+   difference between `config_opts['macros']['foo'] = 'baz'` vs.
+   `config_opts['macros']['%foo'] = 'baz'`), mock on newer systems
+   (with new-enough Python 3.8+) failed hard with not really helpful
+   error.  This has been fixed (issue#605).
+
+## Mock-core-configs v33 changes:
+
+ * New Fedora ELN config files are provided.
+
+ * Some adjustments were done for the new mock-filesystem package.
+
+
+Following contributors contributed to this release:
+
+ * Miroslav Suchý
+ * Pat Riehecky
+
+Thank you.