Fix CI!

Turns out the drone config is NOT supported by woodpecker.

.drone.yml

@@ -1,8 +0,0 @@
-kind: pipeline
-name: default
-
-steps:
-- name: build
-  image: golang
-  commands:
-  - make build

.woodpecker/build.yml

@@ -0,0 +1,12 @@
+platform: linux/amd64
+
+pipeline:
+  format:
+    image: golang
+    commands:
+      - files=$(gofmt -l .) && echo "$files" && [ -z "$files" ]
+  build:
+    image: golang
+    commands:
+      - make build
+