Properly build a PIE binary

.gitlab-ci.yml

@@ -7,7 +7,7 @@ compile:
   image: golang:alpine
   script:
     - source ./env
-    - go build -tags "$TAGS" -ldflags "$LDFLAGS" ./cmd/hepto.go
+    - go build -buildmode=pie -tags "$TAGS" -ldflags "$LDFLAGS" ./cmd/hepto.go
   artifacts:
     paths:
       - hepto