fix: explicitly set GOROOT to make golangci happy

.drone.yml

@@ -138,6 +138,7 @@ steps:
       GOPROXY: 'https://goproxy.kolaente.de'
     depends_on: [ build ]
     commands:
+      - export "GOROOT=$(go env GOROOT)"
       - apk --no-cache add build-base git
       - wget -O - -q https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.47.3
       - ./mage-static check:all
@@ -878,6 +879,6 @@ steps:
         - failure
 ---
 kind: signature
-hmac: a1f0766e0d0774202888c4bea1904ee6dfff6b51b11459a2f95d97c6e0d08a26
+hmac: 86551cd9d31a1cadad5addfa97a249763a9ef7f2f5e46ea4105802aeef25efb9
 
 ...