Release v0.20.0

Changelog

• 2bdf6fc chore(deps): bump docker/login-action (#384)
• 30e5cd2 chore(deps): bump the docker-compose-all group with 3 updates (#385)
• 69911ae chore(deps): bump the docker-compose-all group with 3 updates (#401)
• 6c47946 chore(deps): bump the ghactions-all group with 4 updates (#400)
• 5003300 chore(deps): bump the gomod-all group with 2 updates (#399)
• a5fbe3b docs: describe the emitted status lifecycle and double-spend semantics (#389)
• e8bc97a feat(events): publish RECEIVED at intake so subscribers see the first state (#391)
• e229a09 feat: API key authorization middleware with per-tier rate limiting (#381)
• cbe4f89 fix(api): render intake reasons once and omit zero times on GET /tx (#388)
• 81852f7 fix(mongodb): decouple the idle pool floor from max_pool_size (#386)
• 64037b1 fix(policy): stop advertising standard-format intake (#387)
• c96718d fix(propagation): key single-tx submits like their in-flight parent (#392)
• 603b48e fix(reconciler): re-watch orphaned txs so a re-mine past merkle's post-mine TTL is seen (#395)
• 8b48db6 fix(store): clear retry bookkeeping when a transaction recovers (#390)