Add uninstall_trunk & update install_trunk makefile command (#103)

Makefile

@@ -7,15 +7,14 @@ bootstrap:
 
 install_trunk:
 	$(eval trunk_installed=$(shell trunk --version > /dev/null 2>&1 ; echo $$? ))
-ifneq ($(trunk_installed),0)
+ifneq (${trunk_installed},0)
 	$(eval OS_NAME=$(shell uname -s | tr A-Z a-z))
-ifeq ($(OS_NAME),linux)
 	curl https://get.trunk.io -fsSL | bash
 endif
-ifeq ($(OS_NAME),darwin)
-	brew install trunk-io
-endif
-endif
+
+uninstall_trunk:
+	sudo rm -if `which trunk`
+	rm -ifr ${HOME}/.cache/trunk
 
 git_hooks: install_trunk
 	trunk fmt