fix: standardize Dockerfile stage names to uppercase

Updates the Dockerfile to use uppercase for multi-stage build
definitions. This change enhances readability and maintains consistency
across the build stages, ensuring alignment with common best practices in
Dockerfile conventions.

Dockerfile

@@ -1,9 +1,9 @@
-FROM golang:1.25.6@sha256:fc24d3881a021e7b968a4610fc024fba749f98fe5c07d4f28e6cfa14dc65a84c as deps
+FROM golang:1.25.6@sha256:fc24d3881a021e7b968a4610fc024fba749f98fe5c07d4f28e6cfa14dc65a84c AS deps
 WORKDIR /build
 ADD go.* /build
 RUN go mod download
 
-FROM deps as build
+FROM deps AS build
 ARG TARGETOS
 ARG TARGETARCH
 
@@ -19,7 +19,7 @@ RUN go tool cover -func=coverage.txt
 RUN rm coverage.txt.tmp
 RUN iGOOS=${TARGETOS} GOARCH=${TARGETARCH} CGO_ENABLED=0 go build -mod=readonly -o release/default-request-adder -ldflags '-w -s'
 
-FROM scratch as export
+FROM scratch AS export
 COPY --from=build /build/coverage.txt /
 
 FROM scratch