feat: add coredns mysql image build and updater

dockerfile

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: MIT
+# Copyright (C) 2026 Bryan Joshua Pedini
+
+FROM golang:1.26-alpine AS build
+RUN apk add --no-cache git ca-certificates
+ARG COREDNS_VERSION
+RUN test -n "$COREDNS_VERSION"
+RUN git clone --depth 1 --branch "v${COREDNS_VERSION}" https://github.com/coredns/coredns.git /src
+WORKDIR /src
+RUN sed -i '/^file:file$/i mysql:github.com/cloud66-oss/coredns_mysql' plugin.cfg
+ARG MYSQL_PLUGIN_REV
+RUN test -n "$MYSQL_PLUGIN_REV"
+RUN go get "github.com/cloud66-oss/coredns_mysql@${MYSQL_PLUGIN_REV}"
+RUN go generate
+RUN CGO_ENABLED=0 go build -trimpath -ldflags='-s -w' -o /coredns .
+
+FROM scratch
+COPY --from=build /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=build /coredns /coredns
+EXPOSE 53 53/udp
+ENTRYPOINT ["/coredns"]