fix(docker): Add missing dependency for IM to work with PDFs

Dockerfile

@@ -20,7 +20,7 @@ RUN pacman --needed --noconfirm -Syuq && yes | pacman -Sccq
 
 # Install CaSILE run-time dependecies (increment cache var above)
 RUN pacman --needed --noconfirm -Syq \
-		bc bcprov cpdf entr epubcheck git imagemagick inetutils inkscape \
+		bc bcprov cpdf entr epubcheck ghostscript git imagemagick inetutils inkscape \
 		java-commons-lang jq kindlegen m4 make moreutils nodejs otf-libertinus \
 		pandoc-sile-git pcre pdftk podofo poppler povray rsync sile sqlite \
 		tex-gyre-fonts texlive-core ttf-hack xcftools yarn yq zint zsh \