Fix go build command in Dockerfile

Author: bootjp

Dockerfile

@@ -3,7 +3,7 @@ FROM golang:latest AS build
 WORKDIR $GOPATH/src/app
 COPY . .
 
-RUN CGO_ENABLED=0 go build -o /app main.go
+RUN CGO_ENABLED=0 go build -o /app .
 
 FROM gcr.io/distroless/static:latest
 COPY --from=build /app /app