Don't add stable if pushed tag has -

.github/workflows/main-docker.yml

@@ -244,7 +244,8 @@ jobs:
             $(printf '${{ env.DOCKERHUB_REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)
 
           # If the ref is a tag, also tag the image as stable as this is part of a 'release'
-          if [[ "${GITHUB_REF}" == refs/tags/* ]]; then
+          # and only go in the `if` if there is NOT a `-` in the tag's name, due to tagging of `-alpha`, `-beta`, etc...
+          if [[ "${GITHUB_REF}" == refs/tags/* && ! "${REF_NAME}" =~ - ]]; then
             docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
               -t ${{ env.GHCR_REGISTRY }}/${{ env.IMAGE_NAME }}:stable \
               $(printf '${{ env.GHCR_REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)