new release v0.3

docker-slimbuild

@@ -0,0 +1,30 @@
+FROM golang:1.13 AS builder
+
+RUN apt-get update && apt-get -y install upx 
+
+#RUN mkdir -p $GOPATH/src/github.com/DTherHtun/google-chat-action
+#ADD . $GOPATH/src/github.com/DTherHtun/google-chat-action
+RUN go get -u github.com/sethvargo/go-githubactions/...
+ENV CGO_ENABLED=0
+COPY . .
+
+RUN go build \
+  -a \
+  -trimpath \
+  -ldflags "-s -w -extldflags '-static'" \
+  -installsuffix cgo \
+  -tags netgo \
+  -o /bin/google-chat-action \
+  . 
+
+RUN strip /bin/google-chat-action
+
+RUN upx -q -9 /bin/google-chat-action
+
+FROM scratch
+
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+
+COPY --from=builder /bin/google-chat-action /bin/google-chat-action
+
+ENTRYPOINT ["/bin/google-chat-action"]