Update alpine, use gitleaks user instead of root (#615)

* Updating alpine, use gitleaks user instead of root

* remove comments

Dockerfile

@@ -4,14 +4,9 @@ ARG ldflags
 COPY . .
 RUN GO111MODULE=on CGO_ENABLED=0 go build -o bin/gitleaks -ldflags "-X="${ldflags} *.go 
 
-FROM alpine:3.11
-RUN apk add --no-cache bash git openssh
+FROM alpine:3.14.1
+RUN adduser -D gitleaks && \
+    apk add --no-cache bash git openssh-client
 COPY --from=build /go/src/github.com/zricethezav/gitleaks/bin/* /usr/bin/
+USER gitleaks
 ENTRYPOINT ["gitleaks"]
-
-# How to use me :
-
-# docker build -t gitleaks .
-# docker run --rm --name=gitleaks gitleaks --repo-url=https://github.com/zricethezav/gitleaks
-
-# This will check for secrets in https://github.com/zricethezav/gitleaks