* NEWS.md: Add 14.1.7 release announcement.
* .github/workflows/spec.yml, Makefile, README.md, bin/specl,
build-aux/config.ld.in, lib/specl/badargs.lua,
lib/specl/color.lua, lib/specl/compat.lua, lib/specl/expect.lua,
lib/specl/formatter/progress.lua, lib/specl/formatter/report.lua,
lib/specl/formatter/tap.lua, lib/specl/inprocess.lua,
lib/specl/loader.lua, lib/specl/main.lua, lib/specl/matchers.lua,
lib/specl/runner.lua, lib/specl/sandbox.lua, lib/specl/shell.lua,
lib/specl/std.lua, lib/specl/util.lua, lib/specl/version-git.lua,
lib/specl/version.lua.in, spec/badargs_spec.yaml,
spec/custom_formatters_spec.yaml, spec/environment_spec.yaml,
spec/formatter/progress_spec.yaml,
spec/formatter/report_spec.yaml, spec/formatter/spec_helper.lua,
spec/inprocess_spec.yaml, spec/loader_spec.yaml,
spec/matchers_spec.yaml, spec/runner_spec.yaml,
spec/shell_spec.yaml, spec/should_spec.yaml,
spec/spec_helper.lua, spec/specl_spec.yaml, spec/util_spec.yaml,
specl-git-1.rockspec, specl.in: Add and document Lua 5.4 support.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>