Catch3 keeps Catch2's API for writing tests (test cases, sections,
assertions, matchers, generators, listeners, benchmarks) and replaces its
session, command line and reporters with a runner of its own.

The runner starts the test binary again as worker processes that take the
next test when they are free. A crash, an exit or a hang ends one test, not
the run. On top of that it adds:

- retries that tell deterministic, flaky and order-dependent failures
  apart, and a bisection that names the test leaving state behind;
- a history of verdicts and durations, kept under a file lock, that drives
  automatic quarantine, adaptive time limits, predictive ordering,
  incremental runs, failure replay and analytics;
- selection by change, past failure or prediction, dependency closure,
  and sharding by a stable hash or by recorded durations;
- tags for serial and isolated tests, shared resources, dependencies,
  time limits and retries;
- a failure category, a signature, an analysis and a replay command for
  every failure;
- console, JUnit XML (with flakyFailure and rerunFailure), JSON and Chrome
  trace reports, and a versioned discovery listing (--list=json);
- a temporary directory per test (TMPDIR, TMP, TEMP and
  TestTemporaryDirectory());
- Bazel's test environment: XML output file, test filter, sharding, seed,
  premature exit file and undeclared outputs.

The command line is parsed by a hand-written, typed parser. Catch::Session
remains as a thin facade over the runner for custom main functions.

The result model in Progmasoft/Catch3/Results.hpp was rewritten around
tests and attempts, and the JUnit writer now writes it. The property
engine's example database is updated under a file lock with an atomic
rename, so parallel workers can write it at the same time.

Removed: Clara, the command-line and reporter-spec parsers, every reporter
and CATCH_REGISTER_REPORTER, listing, text flow, console colour and width,
the JSON and XML writers, sharding in the test registry, approval tests and
their baselines, Conan packaging, and the unused third_party/clara.hpp.
Listeners keep working; reporters' list and skip events are gone.

The Catch2 library is now compiled as C++20; code that includes only
Catch2's headers still needs C++14. Duplicate test cases are still refused
at start-up. Version 0.3.0.

ExtraTests now turn exceptions off for clang-cl with MSVC-style options,
which -fno-exceptions did not do.

Introduce deterministic property execution, built-in generators, shrinking, replayable seeds, and a separate Progmasoft-owned header API while preserving Catch2 compatibility targets and the C++14 engine baseline.

Add Bazel, Meson, Xmake, and Premake integration and tests alongside the existing CMake build. Replace Linux-only workflow coverage with Windows and macOS jobs and document the Catch2/Catch3 distinction.

This PR primarily accomplishes two tasks:

1) It adds MODULE.bazel.lock to the .gitignore file.
2) It includes a Bazel build rule for SelfTest, which can be utilized with the command bazel test //tests:catch2_self_test.

* Removed Conan1 build.py file using conan package tools that are no longer supported

* Working conan 1 and 2 build with the test package. 

updated the test_package to be updated to conan 2 and fixed missing cmake. Still need to check that the license file is packaged up and that the packages look identical before the changes

* Removing debug prints and the license check that isn't working yet

* Working license file copied over as it was before

* Migrated the properties of cpp_info to conan 2. Keeping conan 1 support by checking the version of conan

https://docs.conan.io/1/migrating_to_2.0/properties.html

* Revert "Removed Conan1 build.py file using conan package tools that are no longer supported"

This reverts commit a606d1dfe6e118199be8a371403717e3e42ad5da.

* Need to add a set_version to parse the version from CMakeLists.txt

Adding a package build yaml to ensure conan keeps building on 1 and 2

* Setting lowercase catch2 for pkg_config and cmake_target_name

* Fixing the namespace for conan file cmake_target_name

The Meson[1] build system makes it easier incorporate third-party
libaries into a project if they also build using Meson.

Let's add a minimal Meson build that's compatible with the CMake build,
along with a GitHub workflow to check that it builds and that at least
the simplest SelfTest runs.

The handling of catch_user_config.hpp is inspired by BUILD.bazel and
doesn't attempt to support any configuratons options. Such features
could be added later.

Meson strongly discourages using wildcards to specify sources, so the
source and header lists are copied from CMakeLists.txt.

Add a new test workflow to test the Meson builds. I was unable to get
these tests to pass with Ubuntu 20.04, so they use Ubuntu 22.04.

I'm neither a CMake nor a Meson expert, but the results seem to work for
me.

[1] https://mesonbuild.com/

Co-authored-by: Mike Crowe <mcrowe@brightsign.biz>