Add container image build script

.containerignore

@@ -0,0 +1,4 @@
+*
+!src
+!Cargo.lock
+!Cargo.toml

Containerfile

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+FROM docker.io/library/alpine AS build
+
+RUN --mount=type=cache,target=/var/cache/apk <<EOS
+xargs apk add <<PKGS
+cargo
+libc-dev
+openssl
+openssl-dev
+rust
+PKGS
+EOS
+
+WORKDIR /src
+
+COPY . .
+
+RUN --mount=type=cache,target=/usr/local/cargo/registry <<EOS
+set -e
+cargo build --release
+cp target/release/updatecheck /updatecheck
+strip /updatecheck
+EOS
+
+
+FROM docker.io/library/alpine
+
+RUN --mount=type=cache,target=/var/cache/apk apk add libgcc openssl
+
+COPY --from=build /updatecheck /usr/local/bin
+
+ENTRYPOINT ["updatecheck"]