0.3.0 Symfony 4, docker

• b099557 .mailmap for changelog (othillo)
• 3038994 added license (othillo)
• 246f2bc use latest Broadway packages (othillo)
• b2ffdc3 Symfony 4.4 (othillo)
• 1439f48 removed unused scripts (othillo)
• e78e7fc less restrictive requirements (othillo)
• c8f6aef added description (othillo)
• 845749e Makefile (othillo)
• 2bfd510 broadway/coding-standard ^1.0 (othillo)
• 0f9460e added Travis CI build status badge (othillo)
• 9f9aa26 applied coding standard (othillo)
• 03d4756 require php >= 7.2 (othillo)
• 8e5a971 Update qandidate/stack-request-id requirement from ^1.1 to ^2.0 (othillo)
• 5130f03 applied coding standard (othillo)
• 5dddf98 strong typing (othillo)
• 5388d49 PHPUnit 8 (othillo)
• f9f1e94 use broadway/coding-standard ~0.1 (othillo)
• 177cfcb applied coding standard, added licence docblocks (othillo)
• fcdbb0e read model, event store creation (othillo)
• f7d2dc2 test PHP 7.1, 7.2 do not selfupdat composer (othillo)
• 1962efe run all tests by default (othillo)
• 62fccd7 Symfony 4 (othillo)
• fa4a3e3 replaced Elasticsearch by simple DBAL read model implementation (othillo)
• d841402 updated dependencies (othillo)
• f424294 use MicroKernelTrait (othillo)
• cfe2a50 use dev environment (othillo)
• 58504f4 documented how to run the demo (othillo)
• 61d9c40 removed MongoDB, Vagrant, docker (othillo)
• 333c29f only test actively supported PHP versions (othillo)
• 7d986b4 configured Stale bot (othillo)