ci: remove Travis CI integration
ci: remove Travis CI integration

we are now using Cirrus CI

spesmilo/electrum,pooler/electrum-ltc,wakiyamap/electrum-mona,spesmilo/electrum,pooler/electrum-ltc,pooler/electrum-ltc,pooler/electrum-ltc,wakiyamap/electrum-mona,wakiyamap/electrum-mona,wakiyamap/electrum-mona,spesmilo/electrum,spesmilo/electrum