Add git (#6)

Author: fmenezes

Dockerfile

@@ -5,6 +5,7 @@ FROM base as builder
 RUN go get -u github.com/fmenezes/codeowners/cmd/codeownerslint
 
 FROM alpine:latest
+RUN apk add --no-cache git
 COPY --from=builder /go/bin/codeownerslint /usr/local/bin/codeownerslint
 COPY entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]