dockerfile: add v2 CI

Signed-off-by: Sumner Evans <sumner.evans@automattic.com>

Dockerfile.v2.ci

@@ -0,0 +1,15 @@
+FROM alpine:3.20
+
+ENV UID=1337 \
+    GID=1337
+
+RUN apk add --no-cache ffmpeg su-exec ca-certificates bash jq curl yq-go
+
+ARG EXECUTABLE=./mautrix-telegram
+COPY $EXECUTABLE /usr/bin/mautrix-telegram
+COPY ./docker-run.sh /docker-run.sh
+ENV BRIDGEV2=1
+VOLUME /data
+WORKDIR /data
+
+CMD ["/docker-run.sh"]