Remove unneeded build steps from Alpine

.docker/Dockerfile.alpine

@@ -23,25 +23,8 @@ RUN apk add --no-cache \
     ca-certificates \
     git \
     python3-dev \
-    py3-pip \
     curl
 
-# On arm64, we need to build cffi from source.
-ARG TARGETPLATFORM
-
-RUN if [ "${TARGETPLATFORM}" == "linux/arm64" ]; then \
-    apk add --no-cache \
-    build-base \
-    autoconf \
-    automake \
-    libtool \
-    zlib-dev \
-    libffi-dev \
-    cairo-dev \
-    pkgconfig \
-    ;  \
-    fi
-
 COPY . /app
 
 WORKDIR /app