Fix #474: explicitly indicate gzip to tar

Makefile

@@ -117,7 +117,7 @@ upload-local: sign static
 	curl -XPOST 'https://uploads.github.com/repos/jarun/nnn/releases/$(ID)/assets?name=nnn-$(VERSION).tar.gz.sig' \
 	    -H 'Authorization: token $(NNN_SIG_UPLOAD_TOKEN)' -H 'Content-Type: application/pgp-signature' \
 	    --upload-file nnn-$(VERSION).tar.gz.sig
-	tar -cf $(BIN)-static-$(VERSION).x86-64.tar.gz $(BIN)-static
+	tar -zcf $(BIN)-static-$(VERSION).x86-64.tar.gz $(BIN)-static
 	curl -XPOST 'https://uploads.github.com/repos/jarun/nnn/releases/$(ID)/assets?name=nnn-$(VERSION)-static-$(VERSION).x86-64.tar.gz' \
 	    -H 'Authorization: token $(NNN_SIG_UPLOAD_TOKEN)' -H 'Content-Type: application/x-sharedlib' \
 	    --upload-file $(BIN)-static-$(VERSION).x86-64.tar.gz