release: rollback Ubuntu to 18.04 (except for riscv64)

Partially revert 0e56e4f9ff

Rollback the build environment from Ubuntu 22.04 to 18.04, except for riscv64 that isn't supported by Ubuntu 18.04.

Fix issue 7255 (`1.6.7 can't be run on Ubuntu LTS 20.04 (GLIBC_2.34 not found)`)

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

.github/workflows/release/Dockerfile

@@ -12,7 +12,8 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
-ARG UBUNTU_VERSION=22.04
+# UBUNTU_VERSION can be set to 18.04 (bionic), 20.04 (focal), or 22.04 (jammy)
+ARG UBUNTU_VERSION=18.04
 ARG BASE_IMAGE=ubuntu:${UBUNTU_VERSION}
 ARG GO_VERSION
 ARG GO_IMAGE=golang:${GO_VERSION}
@@ -25,7 +26,8 @@ SHELL ["/bin/bash", "-xec"]
 RUN	apt-get update && \
 	apt-get install -y dpkg-dev git make pkg-config
 ARG TARGETPLATFORM
-RUN xx-apt-get install -y libseccomp-dev libbtrfs-dev gcc
+RUN xx-apt-get install -y libseccomp-dev btrfs-progs gcc
+RUN if grep -qE 'UBUNTU_CODENAME=(focal|jammy)' /etc/os-release; then xx-apt-get install -y libbtrfs-dev; fi
 ENV PATH=/usr/local/go/bin:$PATH
 ENV GOPATH=/go
 ENV CGO_ENABLED=1