Update alpine:latest Docker digest to b89d9c9

Dockerfile

@@ -15,7 +15,7 @@ COPY *.go ./
 RUN go build -o confluence-gardner
 
 # final stage
-FROM alpine:latest@sha256:77726ef6b57ddf65bb551896826ec38bc3e53f75cdde31354fbffb4f25238ebd
+FROM alpine:latest@sha256:b89d9c93e9ed3597455c90a0b88a8bbb5cb7188438f70953fede212a0c4394e0
 COPY --from=build-env /go/src/confluence-gardner/confluence-gardner  /usr/local/bin/confluence-gardner
 RUN mkdir -p /output
 ENV DIRECTORY /output