Revert "Update the image texlive/texlive:pretest from a regular mir…

…ror"

This reverts commit 8f8e131.

Dockerfile

@@ -75,6 +75,9 @@ apt-get -qy install --no-install-recommends ${DEPENDENCIES}
 if echo ${TEXLIVE_TAG} | grep -q latest
 then
   retry -t 30 -d 60 tlmgr update --self --all
+elif echo ${TEXLIVE_TAG} | grep -q pretest
+then
+  retry -t 30 -d 60 tlmgr update --self --all --repository ftp://ftp.cstug.cz/pub/tex/local/tlpretest/
 fi
 
 # Generate the ConTeXt file database
@@ -164,6 +167,9 @@ rm -rfv ${AUXILIARY_FILES}
 if echo ${TEXLIVE_TAG} | grep -q latest
 then
   retry -t 30 -d 60 tlmgr update --self --all
+elif echo ${TEXLIVE_TAG} | grep -q pretest
+then
+  retry -t 30 -d 60 tlmgr update --self --all --repository ftp://ftp.cstug.cz/pub/tex/local/tlpretest/
 fi
 
 # Uninstall the distribution Markdown package