sphobjinv v2.4

What's Changed

• Merge v2.3.1.3 release branch back into main by @bskinn in #319
• Fix GitHub badge by @bskinn in #320
• Convert most remote inventory fetch tests to use a local server; bump Pythons and dev Sphinx by @bskinn in #325
• Lints config maintenance by @bskinn in #327
• Implement sphobjinv-textconv and remove CLI implementation section from docs by @bskinn in #331
• Update test infra & migrate http:// links to https:// by @bskinn in #333
• Release 2.4 by @bskinn in #336

Full Changeset: v2.3.1.3...v2.4