Workers and the other processes the runner starts copied its whole
environment, tokens and passwords included. ChildProcess::Start now
leaves out every variable whose name contains, in any case, TOKEN,
SECRET, PASSWORD, PASSWD, CREDENTIAL, API_KEY, APIKEY, PRIVATE_KEY or
ACCESS_KEY (IsSecretVariable), unless ChildOptions::keptEnvironment
names it; names compare without case on Windows.

--pass-env=NAME, repeatable, and "pass-env" in catch3.json keep a
variable for the tests. The runner itself still starts with the whole
environment, so code that runs before the first worker sees it;
docs/progmasoft-runner.md says so.

A runner test starts the shell's environment listing with a secret and
a plain variable set, sees only the plain one, and sees the secret once
it is kept.

Version 1.1 left programs built with Progmasoft tools under MPL-2.0 duties
for the code the tools place in them, and left other cases unclear.
Version 2.0 adds a generated code permission, covers runtime and standard
libraries, compiler transformations, interfaces and examples, and settles
how a file is identified and how to tell recipients about source.

Every project SPDX expression moves to AdditionRef-Progmasoft-Exception-2.0.
The older texts stay, because released versions name them.

Listeners that print while they are created raced with the first test:
the text went through the worker's error stream and could reach the
runner after it had given the worker a test, which then claimed it as its
own output. The worker now captures Catch2's standard streams while it
creates the listeners and starts the run, sends the text in its hello
message, and the runner writes it to its standard error.

Catch2's stream redirect now remembers the buffer to restore when a
redirect starts rather than when it is made, so a stream whose buffer
changed in between is restored to the right one.

ExtraTests X21 and X27 defined their listeners at namespace scope, which
clang rejects under -Wweak-vtables with -Werror on Linux and macOS; they
are now in anonymous namespaces.

After a fatal signal Catch2 closes the open sections itself, so on POSIX a
crash was reported outside the section it happened in. The scheduler now
ignores section ends that follow a fatal condition.

New unit tests cover the planner (every selection, dependency closure and
cycles, hash and duration shards, incremental runs, learned time limits,
ordering, retries, quarantine and replay), every command-line option and
its errors, and the failure analysis (history classes, signature groups,
crash and hang locations, changed files, replay commands).
Catalog::FromEntries builds a catalog without a test registry so the
planner can be tested on its own.

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.