chore: resolve open dependabot security alerts

- markdownlint-cli ^0.44.0 -> ^0.48.0 (fixes minimatch, glob, js-yaml v4 alerts 18, 12, 8)
- markdown-link-check ^3.10.2 -> ^3.14.2 (fixes basic-ftp alerts 16 and 22)
- js-yaml 3.14.1 -> 3.14.2 (medium, alert 9; resolves naturally via lockfile refresh)
- lodash.template 4.5.0 -> 4.18.1 (high, alerts 1 and 21; override required, markdown-toc dep chain is frozen)

Signed-off-by: Jonathan Norris <jonathan.norris@dynatrace.com>

Author: jonathannorris