chore: Fix Dockerfile FROM/AS Casing (runatlantis#5030)

Signed-off-by: X-Guardian <[email protected]>

Dockerfile

@@ -44,7 +44,7 @@ RUN --mount=type=cache,target=/go/pkg/mod \
     --mount=type=cache,target=/root/.cache/go-build \
     CGO_ENABLED=0 go build -trimpath -ldflags "-s -w -X 'main.version=${ATLANTIS_VERSION}' -X 'main.commit=${ATLANTIS_COMMIT}' -X 'main.date=${ATLANTIS_DATE}'" -v -o atlantis .
 
-FROM debian:${DEBIAN_TAG} as debian-base
+FROM debian:${DEBIAN_TAG} AS debian-base
 
 # Install packages needed to run Atlantis.
 # We place this last as it will bust less docker layer caches when packages update
@@ -64,7 +64,7 @@ RUN apt-get update && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
-FROM debian-base as deps
+FROM debian-base AS deps
 
 # Get the architecture the image is being built for
 ARG TARGETPLATFORM