Golang docker multi-stage build failing to run: exec: "go": executable file not found in $PATH

When deploying a simple API with a Docker multi-stage build the following error is being thrown:

$ docker build -t api:latest .
[...]
$ docker run -p 4880:4880 --rm --name=api api:latest
2019/01/29 23:02:15 exec: "go": executable file not found in $PATH

As my application is not calling go from anywhere (or any exec.Command) I ran a go mod vendor so I could check the dependency source code and found the following:

vendor/github.com/lib/pq/oid/gen.go
12:     "os/exec"
64:     cmd := exec.Command("gofmt")

Could this be the issue and if so how can I fix it? I am sure I have managed to deploy github.com/lib/pq in a multi-stage build before but I am currently stuck.

Many thanks and Happy Hacking.

Dockerfile

FROM golang:1-alpine AS builder
ENV GO111MODULE=on
RUN apk --no-cache add ca-certificates git
WORKDIR /app
# Copy go module info first...
COPY go.mod .
COPY go.sum .
# ...then download to cache dependencies between builds
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -installsuffix cgo -ldflags '-extldflags "-static"' -o api cmd/api/

FROM scratch
WORKDIR /app
COPY --from=builder /app/api /app/
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
EXPOSE 8080
ENTRYPOINT ["./api"]