added arm64 to ci builds

.drone.yml

@@ -44,6 +44,31 @@ volumes:
 depends_on:
   - cleanup-before
 
+---
+kind: pipeline
+type: docker
+name: default-linux-arm64
+
+steps:
+  - name: build
+    image: golang
+    commands:
+      - ./ci-build.sh build
+    environment:
+      GOOS: linux
+      GOARCH: arm64
+    volumes:
+      - name: build
+        path: /build
+
+volumes:
+  - name: build
+    host:
+      path: /tmp/go-aptproxy/build
+
+depends_on:
+  - cleanup-before
+
 ---
 kind: pipeline
 type: docker
@@ -92,6 +117,7 @@ volumes:
 
 depends_on:
   - default-linux-amd64
+  - default-linux-arm64
 
 ---
 kind: pipeline