deb: fix version to allow for distro upgrades

The existing version format for our packages use `distro-codename` in the version.
Unfortunately, `codename` cannot be used to compare versions, which means that
when a user upgrades their distro to a new version, the package won't be updated
until a new release happens.

This patch changes the format of the version to include `VERSION_ID`, which is
numeric, and can be used in version comparison.

While we're making changes, this also adds an extra `pkgRevision` number in the
version, which can allow us to do a new build/release of a package in between
upstream releases. This version is not yet configurable (which can be changed
in future).

Resulting packages are now formatted as;

- name of the package (e.g., "docker-ce")
- version (e.g., "22.10.6~beta.0")
- "-0" (mostly "best practice", and allows updating for specific situations)
- distro (e.g., "ubuntu")
- VERSION_ID (e.g. "22.04" or "11") this must be "sortable" to make sure that
  packages are upgraded when upgrading to a newer distro version ("codename"
  cannot be used for this, as they're not sorted)
- pkgRevision (usually "0", see above)
- SUITE ("codename"), e.g. "jammy" or "bullseye". This is mostly for convenience,
  because some places refer to distro versions by codename, others by version.
  we prefix the codename with a tilde (~), which effectively excludes it from
  version comparison.

Note that while the `${EPOCH}${EPOCH_SEP}` is part of the version, it is not
included in the package's *filename*.

Examples:

    docker-ce_22.10.6~beta.0-0~debian.11.0~bullseye_amd64.deb
    docker-ce_22.10.6~beta.0-0~ubuntu.22.04.0~jammy_amd64.deb

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

deb/build-deb

@@ -43,8 +43,40 @@ debSource="$(awk -F ': ' '$1 == "Source" { print $2; exit }' debian/control)"
 debMaintainer="$(awk -F ': ' '$1 == "Maintainer" { print $2; exit }' debian/control)"
 debDate="$(date --rfc-2822)"
 
+versionID="$(. /etc/os-release && echo "$VERSION_ID")"
+
+# Include an extra `.0` in the version, in case we ever would have to re-build an
+# already published release with a packaging-only change.
+pkgRevision=0
+
+# Generate changelog. The version/name of the generated packages are based on this.
+#
+# Resulting packages are formatted as;
+#
+# - name of the package (e.g., "docker-ce")
+# - version (e.g., "22.10.6~beta.0")
+# - "-0" (mostly "best practice", and allows updating for specific situations)
+# - distro (e.g., "ubuntu")
+# - VERSION_ID (e.g. "22.04" or "11") this must be "sortable" to make sure that
+#   packages are upgraded when upgrading to a newer distro version ("codename"
+#   cannot be used for this, as they're not sorted)
+# - pkgRevision (usually "0", see above)
+# - SUITE ("codename"), e.g. "jammy" or "bullseye". This is mostly for convenience,
+#   because some places refer to distro versions by codename, others by version.
+#   we prefix the codename with a tilde (~), which effectively excludes it from
+#   version comparison.
+#
+# Note that while the `${EPOCH}${EPOCH_SEP}` is part of the version, it is not
+# included in the package's *filename*. (And if you're wondering: we needed the
+# EPOCH because of our use of CalVer, which made version comparing not work in
+# some cases).
+#
+# Examples:
+#
+# docker-ce_22.10.6~beta.0-0~debian.11.0~bullseye_amd64.deb
+# docker-ce_22.10.6~beta.0-0~ubuntu.22.04.0~jammy_amd64.deb
 cat > "debian/changelog" <<-EOF
-$debSource (${EPOCH}${EPOCH_SEP}${DEB_VERSION}-0~${DISTRO}-${SUITE}) $SUITE; urgency=low
+$debSource (${EPOCH}${EPOCH_SEP}${DEB_VERSION}-0~${DISTRO}.${versionID}.${pkgRevision}~${SUITE}) $SUITE; urgency=low
   * Version: $VERSION
  -- $debMaintainer  $debDate
 EOF