Fixed build stage names in Dockerfile

Author: thordy

Dockerfile

@@ -1,6 +1,6 @@
 # Create our build image
 # Must be node-18, ref https://github.com/docker/build-push-action/issues/1071
-FROM node:18-alpine AS BUILD_IMAGE
+FROM node:18-alpine AS build_image
 
 # Add git and curl
 RUN apk update && apk add --no-cache git curl
@@ -24,7 +24,7 @@ FROM node:22-alpine
 WORKDIR /usr/src/kcapp
 
 # Copy required files from build image
-COPY --from=BUILD_IMAGE /usr/src/kcapp /usr/src/kcapp
+COPY --from=build_image /usr/src/kcapp /usr/src/kcapp
 
 EXPOSE 3000
 CMD [ "npm", "run", "docker" ]