chore(_dev): Fix annotation warnings

Because:
- Docker job in github complained about this (e.g. https://github.com/mozilla/fxa/actions/runs/11060387844)

This Commit:
- changes as to AS, which is stylistically better

_dev/docker/ci/Dockerfile

@@ -4,7 +4,7 @@
 
 # Runs tests and common CI operations. Needs minimal install. Assumes
 # workspace will be restored into the project folder.
-FROM cimg/node:20.11 as test-runner
+FROM cimg/node:20.11 AS test-runner
 RUN sudo apt-get update && sudo apt-get install -y \
     python3-venv
 WORKDIR /home/circleci
@@ -17,7 +17,7 @@ RUN cp yarn.lock yarn.lock.base;
 # Runs initial build stage in CI. Needs full install. Responsible for
 # setting up the initially workspace state. This image installs npm
 # packages and builds heavily referenced workspaces.
-FROM test-runner as builder
+FROM test-runner AS builder
 WORKDIR /home/circleci
 COPY --chown=circleci:circleci .yarn .yarn
 WORKDIR /home/circleci/project
@@ -31,13 +31,13 @@ RUN yarn install --immutable;
 # of firefox is installed. Also note that the functional-test-runner
 # must based on cimg/node:20.11-browsers, which is why this stage
 # is necessary.
-FROM builder as playwright-install
+FROM builder AS playwright-install
 RUN npx playwright install --with-deps firefox chromium webkit;
 
 
 # Runs functional tests in our CI. Needs minimal install. Assumes
 # workspace will be restored into the project folder.
-FROM cimg/node:20.11-browsers as functional-test-runner
+FROM cimg/node:20.11-browsers AS functional-test-runner
 WORKDIR /home/circleci
 COPY --chown=circleci:circleci --from=playwright-install /home/circleci/.cache/ms-playwright .cache/ms-playwright/
 COPY --chown=circleci:circleci project project

_dev/docker/mono/Dockerfile

@@ -12,7 +12,7 @@ RUN set -x \
     app
 
 # Utilities for fxa build
-FROM fxa-base as fxa-build-utils
+FROM fxa-base AS fxa-build-utils
 RUN apt-get update && apt-get install -y \
     git-core \
     python3-setuptools \
@@ -25,7 +25,7 @@ RUN apt-get update && apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 
 # Utilities for fxa services
-FROM fxa-base as fxa-utils
+FROM fxa-base AS fxa-utils
 RUN apt-get update && apt-get install -y \
     netcat-traditional \
     openssl \
@@ -35,14 +35,14 @@ RUN apt-get update && apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 
 # Build mono repo
-FROM fxa-build-utils as fxa-build
+FROM fxa-build-utils AS fxa-build
 COPY --chown=app:app . /fxa
 USER app
 WORKDIR /fxa
 RUN _dev/docker/mono/build.sh $(cat packages/version.json | jq -r '.version.version')
 
 # Final image
-FROM fxa-utils as fxa-mono
+FROM fxa-utils AS fxa-mono
 COPY --from=fxa-build --chown=app:app /fxa /fxa
 COPY --from=fxa-build --chown=app:app /fxa/packages/version.json /app/version.json
 USER app