Update base R image.

The `as.POSIXct.numeric` function was relaxed a bit in R 4.3.0 and made
its "origin" parameter optional, and we need that feature.

For some reason the dependency installation was failing. Using `pak`
seems to fix it. pak is generally a bit faster and more reliable anyway.

docker/Dockerfile

@@ -1,27 +1,15 @@
-FROM rocker/r-ver:4.1
+FROM rocker/r-ver:4.4
 
-RUN apt-get update &&  apt-get install -y --no-install-recommends \
-        git \
-        libcurl4-openssl-dev \
-        libhiredis-dev \
-        libssl-dev \
-        zlib1g-dev \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*
+RUN install2.r pak
 
-# Without this, we are unable to pick up more recent packages
-COPY docker/Rprofile.site /usr/local/lib/R/etc/Rprofile.site
-
-COPY DESCRIPTION /tmp/DESCRIPTION
-
-RUN install2.r --error remotes &&  \
-        Rscript -e 'remotes::install_deps("/tmp")'
+COPY DESCRIPTION /src/DESCRIPTION
+RUN Rscript -e "pak::local_install_deps('/src')"
 
 COPY . /src
-RUN R CMD INSTALL --install-tests /src && rm -rf /src
+RUN Rscript -e "pak::local_install('/src')"
 
 COPY docker/bin /usr/local/bin/
-
+ 
 RUN git config --global --add safe.directory "*"
 RUN echo ".packit" > /.gitignore
 RUN git config --global core.excludesFile "/.gitignore"