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-2.12.md

@@ -0,0 +1,58 @@
+---
+layout: default
+title: Release Notes 2.12
+---
+
+Released on - 2021-07-19
+
+
+## Mock 2.12 bugfixes:
+
+This is rather a small bugfix release, the most interesting stuff has been done
+in mock-core-configs package (see below).
+
+ * We don't set --cwd for --shell mode when a systemd-nspawn without the
+   `--chdir` option is installed on the sytem (typically el7)
+
+ * An RPM `addMacro()` traceback fixed.  The SCM plugin was fixed to explicitly
+   convert the configured macro macro values (in e.g.
+   `config_opts['macros']['%_platform_multiplier'] = 10`) to strings.
+   [[PR 753][PR#753]]
+
+ * Explicitly disabled versionlock DNF plugin by default, as we don't want to
+   affect the builds. [[PR 747][PR#747]]
+
+ * Mock package requirement on `shadow-utils` was removed from
+   `mock-core-configs` to proper `mock-filesystem`. [[PR 743][PR#743]]
+
+
+## Mock-core-configs v34.6:
+
+ * CentOS Stream 9 "preview" files added
+
+ * Rocky Linux configs added
+
+ * AlmaLinux 8 AArch64 configs added.
+
+ * Add AlmaLinux Devel repo as an optional repo for AlmaLinux 8.
+
+ * Fixed GPG key path for SLE updates in openSUSE Leap 15.3.
+
+ * Switch CentOS templates to use quay.io images for bootstrap.
+
+ * EPEL Next 8 configs added.
+
+The following contributors contributed to this release:
+
+ * Carl George
+ * Igor Raits
+ * Louis Abel
+ * Miroslav Suchý
+ * Neal Gompa
+ * Scott K Loga
+
+Thank you!
+
+[PR#747]: https://github.com/rpm-software-management/mock/pull/743
+[PR#747]: https://github.com/rpm-software-management/mock/pull/747
+[PR#753]: https://github.com/rpm-software-management/mock/pull/753