feat: add deploy steps

- add deployment steps to droneci
- update makefile to use droneci workspace

Makefile

@@ -1,6 +1,6 @@
 .PHONY: all prep download build clean
 
-RPMBUILD := $(HOME)/rpmbuild
+RPMBUILD := /drone/src/rpmbuild
 SOURCES := $(RPMBUILD)/SOURCES
 SPECS := $(RPMBUILD)/SPECS
 SPECFILE := gonic.spec
@@ -23,7 +23,7 @@ download: prep
 
 build: $(SPECFILE) download
 	@echo "Building RPM..."
-	@rpmbuild -ba $(SPECFILE)
+	@rpmbuild -ba --define "_topdir $(RPMBUILD)" $(SPECFILE)
 	@echo "RPM built."
 
 clean: