devops: simplify Docker publishing (#1481)

utils/docker/publish_docker.sh

@@ -29,11 +29,6 @@ else
   exit 1
 fi
 
-if [[ -z "${GITHUB_SHA}" ]]; then
-  echo "ERROR: GITHUB_SHA env variable must be specified"
-  exit 1
-fi
-
 FOCAL_TAGS=(
   "next-focal"
 )
@@ -46,7 +41,6 @@ fi
 JAMMY_TAGS=(
   "next"
   "next-jammy"
-  "sha-${GITHUB_SHA}"
 )
 
 if [[ "$RELEASE_CHANNEL" == "stable" ]]; then