v5.0.2

What's Changed

• docs: improve documentation by @jeremylong in #84
• fix: add retry on 503 errors by @jeremylong in #90
• fix: add 429 errors to retry by @jeremylong in #92
• fix: honor retry after header by @jeremylong in #94
• fix: cancel futures during failure by @jeremylong in #91

Full Changelog: v5.0.1...v5.0.2