Add worksapce to drone.yml

.drone.yml

@@ -1,6 +1,10 @@
 kind: pipeline
 name: default
 
+workspace:
+  base: /go
+  path: src/deadbeef.codes/steven/mandelmapper
+
 steps:
 - name: build
   image: golang
@@ -9,7 +13,6 @@ steps:
     GOOS: linux
     GOARCH: amd64
     CGO_ENABLED: 0
-    GOPATH: /drone/src
   commands:
   - go version
   - go get