go: update modules

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/github.com/urfave/cli/v2/Makefile

@@ -0,0 +1,40 @@
+# NOTE: this Makefile is meant to provide a simplified entry point for humans to
+# run all of the critical steps to verify one's changes are harmonious in
+# nature. Keeping target bodies to one line each and abstaining from make magic
+# are very important so that maintainers and contributors can focus their
+# attention on files that are primarily Go.
+
+.PHONY: all
+all: generate vet tag-test test check-binary-size tag-check-binary-size gfmrun v2diff
+
+# NOTE: this is a special catch-all rule to run any of the commands
+# defined in internal/build/build.go with optional arguments passed
+# via GFLAGS (global flags) and FLAGS (command-specific flags), e.g.:
+#
+#   $ make test GFLAGS='--packages cli'
+%:
+	go run internal/build/build.go $(GFLAGS) $* $(FLAGS)
+
+.PHONY: tag-test
+tag-test:
+	go run internal/build/build.go -tags urfave_cli_no_docs test
+
+.PHONY: tag-check-binary-size
+tag-check-binary-size:
+	go run internal/build/build.go -tags urfave_cli_no_docs check-binary-size
+
+.PHONY: gfmrun
+gfmrun:
+	go run internal/build/build.go gfmrun docs/v2/manual.md
+
+.PHONY: docs
+docs:
+	mkdocs build
+
+.PHONY: docs-deps
+docs-deps:
+	pip install -r mkdocs-requirements.txt
+
+.PHONY: serve-docs
+serve-docs:
+	mkdocs serve