cannon: Restore cannon version arg.

Author: ajsutton

ops/docker/op-stack-go/Dockerfile

@@ -50,6 +50,7 @@ ARG TARGETARCH
 FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/cannon:v1.0.0-alpha.3 AS cannon-builder-0
 
 FROM --platform=$BUILDPLATFORM builder AS cannon-builder
+ARG CANNON_VERSION=v0.0.0
 COPY --from=cannon-builder-0 /usr/local/bin/cannon ./cannon/multicannon/embeds/cannon-0
 RUN --mount=type=cache,target=/go/pkg/mod --mount=type=cache,target=/root/.cache/go-build cd cannon && make cannon  \
   GOOS=$TARGETOS GOARCH=$TARGETARCH GITCOMMIT=$GIT_COMMIT GITDATE=$GIT_DATE VERSION="$CANNON_VERSION"