Remove .drone.yml

Drone CI is gone for a while now.

.drone.yml

@@ -1,15 +0,0 @@
-kind: pipeline
-type: docker
-name: default
-
-steps:
-- name: submodules
-  image: alpine/git
-  commands:
-  - git clone https://github.com/alanorth/hugo-theme-bootstrap4-blog.git themes/hugo-theme-bootstrap4-blog
-- name: build
-  image: klakegg/hugo:ext-alpine
-  commands:
-  - hugo
-
-# vim: ts=2 sw=2 et