Try to mitigate newline

.gitattributes

@@ -1,3 +1,3 @@
 *.sh text eol=lf
-#The #! won't work if CRLF
-/Installer/debian/docker/debian/rules text eol=lf
+#The #! in rules won't work if CRLF
+/Installer/debian/docker/debian/* text eol=lf

Installer/debian/build.sh

@@ -5,7 +5,8 @@ SCRIPTDIR=$( cd "$(dirname "$0")" ; pwd -P )
 
 docker build $SCRIPTDIR/docker -t duplicati-debian
 
-export VERSION=`grep '<Version>' < $SCRIPTDIR/../../Duplicati/Server/Duplicati.Server.csproj | sed 's/.*<Version>\(.*\)<\/Version>/\1/'`
+VERSION=`grep '<Version>' < $SCRIPTDIR/../../Duplicati/Server/Duplicati.Server.csproj | sed 's/.*<Version>\(.*\)<\/Version>/\1/'`
+VERSION=${VERSION//$'\n'}
 echo Building version: $VERSION
 
 export MSYS_NO_PATHCONV=1

Installer/debian/docker/runner.sh

@@ -3,6 +3,8 @@ cd /deb
 DATE_STAMP=$(LANG=C date -R)
 sed -e "s;%VERSION%;$VERSION;g" -e "s;%DATE%;$DATE_STAMP;g" -i "debian/changelog"
 
+cat debian/changelog
+
 cp /sources/changelog.txt ./
 
 dpkg-buildpackage -b --no-sign