v0.18.1

See the readme, and use the following in MODULE.bazel:

archive_override(
    module_name = "rules_markdown",
    integrity = "sha384-EY5X0chqQ0g8HVEuhYr06UhJosIHVvDvzVGPIFy4Jv4kHNV/bBimnUMcgA5LUsT1",
    strip_prefix = "rules_markdown-0.18.1",
    urls = "https://github.com/calliecameron/rules_markdown/archive/refs/tags/v0.18.1.tar.gz",
)

Changes

• Big speed improvements.
• Fixed the new package script generating incorrect build files.