v0.3.5

Uses the latest version of @backstage/mkdocs-techdocs-core at v0.2.1, which...

• Added support for .yaml file extension support on mkdocs.y(a)ml in monorepo contexts [backstage/mkdocs-monorepo-plugin#59]
• Added the ability for site_names in !include'd mkdocs sites to contain non-URL friendly characters [backstage/mkdocs-monorepo-plugin#58]