Install latest rustc/cargo

The cryptography Python package requires rustc >= 1.65.0 to build
now, and Debian only comes with 1.63.0 by default. We therefore
utilize the rustup installation script, similar to the get-pip.py
script, to get the latest version.

src/Dockerfile

@@ -34,7 +34,6 @@ RUN set -ex && \
     apt-get update && \
     apt-get install -y --no-install-recommends \
             build-essential \
-            cargo \
             curl \
             libffi8 \
             libffi-dev \
@@ -45,6 +44,9 @@ RUN set -ex && \
             python3 \
             python3-dev \
     && \
+# Install the latest version of rustc/cargo.
+    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && \
+    . "$HOME/.cargo/env" && \
 # Install the latest version of PIP, Setuptools and Wheel.
     curl -L 'https://bootstrap.pypa.io/get-pip.py' | python3 && \
 # Install certbot.
@@ -54,18 +56,17 @@ RUN set -ex && \
 # Remove everything that is no longer necessary.
     apt-get remove --purge -y \
             build-essential \
-            cargo \
             curl \
             libffi-dev \
             libssl-dev \
             pkg-config \
             python3-dev \
     && \
+    rustup self uninstall -y && \
     apt-get autoremove -y && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/* && \
     rm -rf /root/.cache && \
-    rm -rf /root/.cargo && \
 # Create new directories and set correct permissions.
     mkdir -p /var/www/letsencrypt && \
     mkdir -p /etc/nginx/user_conf.d && \

src/Dockerfile-alpine

@@ -33,7 +33,6 @@ RUN set -ex && \
 # Install packages necessary during the build phase (for all architectures).
     apk add --no-cache \
         bash \
-        cargo \
         curl \
         findutils \
         libffi \
@@ -46,6 +45,9 @@ RUN set -ex && \
         python3-dev \
         sed \
     && \
+# Install the latest version of rustc/cargo.
+    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && \
+    . "$HOME/.cargo/env" && \
 # Install the latest version of PIP, Setuptools and Wheel.
     curl -L 'https://bootstrap.pypa.io/get-pip.py' | python3 && \
 # Install certbot.
@@ -54,14 +56,13 @@ RUN set -ex && \
     pip3 install $(echo $CERTBOT_DNS_AUTHENTICATORS | sed 's/\(^\| \)/\1certbot-dns-/g') && \
 # Remove everything that is no longer necessary.
     apk del \
-        cargo \
         curl \
         libffi-dev \
         libressl-dev \
         python3-dev \
     && \
+    rustup self uninstall -y && \
     rm -rf /root/.cache && \
-    rm -rf /root/.cargo && \
 # Create new directories and set correct permissions.
     mkdir -p /var/www/letsencrypt && \
     mkdir -p /etc/nginx/user_conf.d && \