Use alpine 3.11 instead of 3.8 (end of support)

Author: itsdalmo

Dockerfile

@@ -4,7 +4,7 @@ WORKDIR /go/src/github.com/telia-oss/github-pr-resource
 RUN curl -sL https://taskfile.dev/install.sh | sh
 RUN ./bin/task build
 
-FROM alpine:3.8 as resource
+FROM alpine:3.11 as resource
 COPY --from=builder /go/src/github.com/telia-oss/github-pr-resource/build /opt/resource
 RUN apk add --update --no-cache \
     git \