Add experimental staticcheck into linting CI

See https://staticcheck.io for more. This is set to be ignored
on failure so that it doesn't disrupt current work flows but maybe
it is nice to add. Just drop the `ignore: ...` line and it will fail
builds.

.drone.yml

@@ -7,6 +7,16 @@ steps:
     commands:
       - make check
 
+  - name: make static
+    image: golang:1.16
+    ignore: true  # until we decide we all want this check
+    environment:
+      STATIC_CHECK_URL: honnef.co/go/tools/cmd/staticcheck
+      STATIC_CHECK_VERSION: v0.2.0
+    commands:
+      - go install $STATIC_CHECK_URL@$STATIC_CHECK_VERSION
+      - make static
+
   - name: make build
     image: golang:1.16
     commands:

Makefile

@@ -4,7 +4,7 @@ GOPATH  := $(shell go env GOPATH)
 VERSION := $(shell cat ./version)
 LDFLAGS := "-X 'main.Commit=$(COMMIT)' -X 'main.Version=$(VERSION)'"
 
-all: run install build clean format check
+all: run install build clean format check static
 
 run:
 	@go run -ldflags=$(LDFLAGS) $(ABRA)
@@ -23,3 +23,6 @@ format:
 
 check:
 	@test -z $$(gofmt -l .) || (echo "gofmt: formatting issue - run 'make format' to resolve" && exit 1)
+
+static:
+	@staticcheck $(ABRA)