Use composer v1. Composer 2 seem to fail some package installs

Makefile

@@ -1,16 +1,16 @@
 export PATH := bin:$(PATH)
 
 staging:
-ifeq (, $(wildcard composer-stable.phar))
-	curl -O https://getcomposer.org/composer-stable.phar
-	chmod a+x composer-stable.phar
+ifeq (, $(wildcard composer.phar))
+	curl -O https://getcomposer.org/download/1.10.20/composer.phar
+	chmod a+x composer.phar
 endif
 
 	git fetch
 	git checkout develop
 	git pull
 	yarn install
-	./composer-stable.phar install
+	./composer.phar install
 	./node_modules/gulp/bin/gulp.js
 	rm -rf silverstripe-cache/
 	mkdir silverstripe-cache/