remove unused deps target

Was getting an error about being unable to make `deps` for target `deps` when these lines were included.

Likely since the amalgamation variable was undefined it was looking for a `deps/` directory for the `deps` target.

Author: tantaman

Makefile

@@ -124,9 +124,6 @@ cache/$(EXTENSION_FUNCTIONS):
 clean-deps:
 	rm -rf deps
 
-.PHONY: deps
-deps: deps/$(SQLITE_AMALGAMATION) deps/$(EXTENSION_FUNCTIONS)
-
 deps/$(SQLITE_VERSION)/sqlite3.h deps/$(SQLITE_VERSION)/sqlite3.c:
 	mkdir -p cache/$(SQLITE_VERSION)
 	curl -LsS $(SQLITE_TARBALL_URL) | tar -xzf - -C cache/$(SQLITE_VERSION)/ --strip-components=1