fix(docs-infra): update (and unpin) dependency versions for preview server (#45390)

Update the `Dockerfile` used to create the preview server to use the
latest stable version of Debian (`bullseye`) and also update package
versions to latest versions.

Also, unpin the versions of installed packages (except for Node.js
related ones) as pinning proved problematic due to many packages
removing old versions from the official repositories.

NOTE:
This change will allow the preview server to be updated on the VM and
take advantage of recent fixes, such as #45349. Currently, the update
fails with the error:
```
E: Version '7.64.0-4+deb10u1' for 'curl' was not found
The command '/bin/sh -c apt-get update -y && apt-get install -y curl=7.64.0-4+deb10u1' returned a non-zero code: 100
```

PR Close #45390

aio/aio-builds-setup/dockerbuild/Dockerfile

@@ -1,5 +1,5 @@
 # Image metadata and config
-FROM debian:buster
+FROM debian:bullseye
 
 LABEL name="angular.io PR preview" \
       description="This image implements the PR preview functionality for angular.io." \
@@ -72,29 +72,29 @@ RUN mkdir /var/log/aio
 
 
 # Add extra package sources
-RUN apt-get update -y && apt-get install -y curl=7.64.0-4+deb10u1
+RUN apt-get update -y && apt-get install -y curl
-RUN curl --silent --show-error --location https://deb.nodesource.com/setup_12.x | bash -
+RUN curl --silent --show-error --location https://deb.nodesource.com/setup_14.x | bash -
 RUN curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
 RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
 
 
 # Install packages
-# NOTE: Some packages (such as `nginx`, `nodejs`, `openssl`) make older versions unavailable on the
+# NOTE: Many packages make older versions unavailable on the repositories, so we cannot pin to
-#       repositories, so we cannot pin to specific versions for these packages :(
+#       specific versions :(
-#       See for example:
+#       See, for example:
 #       - https://github.com/nodesource/distributions/issues/33
 #       - https://askubuntu.com/questions/715104/how-can-i-downgrade-openssl-via-apt-get
 RUN apt-get update -y && apt-get install -y \
-    cron=3.0pl1-134+deb10u1 \
+    cron \
-    dnsmasq=2.80-1 \
+    dnsmasq \
-    nano=3.2-3 \
+    nano \
     nginx \
     nodejs \
     openssl \
-    rsyslog=8.1901.0-1 \
+    rsyslog \
-    vim=2:8.1.0875-5 \
+    vim \
-    yarn=1.22.4-1
+    yarn=1.22.18-1
-RUN yarn global add pm2@4.4.0
+RUN yarn global add pm2@5.2.0
 
 
 # Set up log rotation