Fixed errors in HTML standalone generation (pandoc) for older versions

Makefile

@@ -19,10 +19,6 @@ pdf: prerequisites-pdflatex clean
 
 html: prerequisites clean
 	@echo "Génération de Output.html"
-	@if pandoc --version | grep -q "pandoc 2\.[0-9]\|pandoc 3"; then \
-		pandoc --defaults=config.yaml -o dist/Output.html --embed-resources --standalone; \
-	else \
-		pandoc --defaults=config.yaml -o dist/Output.html --self-contained --standalone; \
-	fi
+	pandoc --defaults=config.yaml -o dist/Output.html --embed-resources --standalone || pandoc --defaults=config.yaml -o dist/Output.html --self-contained --standalone
 
 all: pdf html
\ No newline at end of file