Updates per comments

move .drone.sh to .drone.yml
Fix Dockerfiles to match S3-cache
Add badges to readme
Couple minor updates to fix variable name and extra space

Dockerfile.arm64

@@ -1,10 +1,20 @@
-FROM alpine:3.3
+
+FROM alpine:3.6 as alpine
+RUN apk add -U --no-cache ca-certificates mailcap
+
+FROM scratch
 MAINTAINER Drone.IO Community <drone-dev@googlegroups.com>
 
-RUN apk update && \
-  apk add \
-    ca-certificates && \
-  rm -rf /var/cache/apk/*
+ENV GODEBUG=netdns=go
+
+COPY --from=alpine /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=alpine /etc/mime.types /etc/
+
+LABEL org.label-schema.version=latest
+LABEL org.label-schema.vcs-url="https://github.com/drone-plugins/drone-webhook.git"
+LABEL org.label-schema.name="Drone Webhook"
+LABEL org.label-schema.vendor="Drone.IO Community"
+LABEL org.label-schema.schema-version="1.0"
 
 ADD release/linux/arm64/drone-webhook /bin/
 ENTRYPOINT ["/bin/drone-webhook"]