fedimint-gateway-startos

docs: standardise package doc set and expand UPDATING.md

s9pk.mk: expose TARGETS via 'make print-TARGETS' for matrix builds

Release 0.11.1:0 — Fedimint Gateway 0.11.1 + start-sdk 1.5.2

Release 0.10.0:2 — Instructions tab + start-sdk 1.5.1

Bump SDK to 1.5.0; add instructions.md; drop docsUrls (#2)