add vendoring

vendor/gitlab.com/etke.cc/linkpearl/Makefile

@@ -0,0 +1,26 @@
+# update go dependencies
+update:
+	go get .
+	go get -u maunium.net/go/mautrix
+	go mod tidy
+
+mock:
+	-@rm -rf mocks
+	@mockery --all
+
+# run linter
+lint:
+	golangci-lint run ./...
+
+# run linter and fix issues if possible
+lintfix:
+	golangci-lint run --fix ./...
+
+vuln:
+	govulncheck ./...
+
+# run unit tests
+test:
+	@go test ${BUILDFLAGS} -coverprofile=cover.out ./...
+	@go tool cover -func=cover.out
+	-@rm -f cover.out