feat: add support for bookworm to v1 Proxy (#2271)

Drop support for buster and add support for bookworm (debian 12) as
buster has fallen out of LTS.

Dockerfile.buster → Dockerfile.bookworm

@@ -23,10 +23,10 @@ ARG TARGETARCH
 
 RUN go get ./...
 RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} \
-    go build -ldflags "-X main.metadataString=container.buster" -o cloud_sql_proxy ./cmd/cloud_sql_proxy
+    go build -ldflags "-X main.metadataString=container.bookworm" -o cloud_sql_proxy ./cmd/cloud_sql_proxy
 
 # Final stage
-FROM gcr.io/cloud-marketplace-containers/google/debian10
+FROM gcr.io/cloud-marketplace-containers/google/debian12
 RUN apt-get update && apt-get install -y ca-certificates
 # Install fuse and allow enable non-root users to mount
 RUN apt-get update && apt-get install -y fuse && sed -i 's/^#user_allow_other$/user_allow_other/g' /etc/fuse.conf

README.md

@@ -45,10 +45,10 @@ currently supported:
 * `$VERSION` - default image (recommended)
 * `$VERSION-alpine` - uses [`alpine:3`](https://hub.docker.com/_/alpine)
   as a base image (only supported from v1.17 up)
-* `$VERSION-buster` - uses [`debian:buster`](https://hub.docker.com/_/debian)
-  as a base image (only supported from v1.17 up)
 * `$VERSION-bullseye` - uses [`debian:bullseye`](https://hub.docker.com/_/debian)
   as a base image (only supported from v1.17 up)
+* `$VERSION-bookworm` - uses [`debian:bookworm`](https://hub.docker.com/_/debian)
+  as a base image (only supported from v1.36 up)
 
 We recommend using the latest version of the proxy and updating the version
 regularly. However, we also recommend pinning to a specific tag and avoid the
@@ -58,7 +58,8 @@ it's a best practice to test changes before deployment, and use automated
 rollbacks to revert potential failures.
 
 **NOTE**: As of v1.16, the default container image uses [distroless][]. If you
-require a shell or similar tools, use the Alpine or Buster images listed above.
+require a shell or similar tools, use the Alpine or Debian based (bullseye
+and bookworm) images listed above.
 
 [distroless]: https://github.com/GoogleContainerTools/distroless