Copy CI workflows from spf13/viper repo

This imports the `ci` workflow from
ab4b05adc6
with one modification noted in the file.

This omits the feedback workflows, as those are not required here.  It
also omits the wasm workflow, as this old snapshot of the code does not
work in that context.

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  build:
+    name: Build
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        go: ['1.14', '1.15', '1.16']
+    env:
+      VERBOSE: 1
+      GOFLAGS: -mod=readonly
+      GOPROXY: https://proxy.golang.org
+
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go }}
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+# the DataDog fork of this repository has many lint failures
+#      - name: Lint
+#        run: make lint
+
+      - name: Test
+        run: make test

Makefile

@@ -0,0 +1,76 @@
+# A Self-Documenting Makefile: http://marmelab.com/blog/2016/02/29/auto-documented-makefile.html
+
+OS = $(shell uname | tr A-Z a-z)
+export PATH := $(abspath bin/):${PATH}
+
+# Build variables
+BUILD_DIR ?= build
+export CGO_ENABLED ?= 0
+export GOOS = $(shell go env GOOS)
+ifeq (${VERBOSE}, 1)
+ifeq ($(filter -v,${GOARGS}),)
+	GOARGS += -v
+endif
+TEST_FORMAT = short-verbose
+endif
+
+# Dependency versions
+GOTESTSUM_VERSION = 1.6.4
+GOLANGCI_VERSION = 1.40.1
+
+# Add the ability to override some variables
+# Use with care
+-include override.mk
+
+.PHONY: clear
+clear: ## Clear the working area and the project
+	rm -rf bin/
+
+.PHONY: check
+check: test lint ## Run tests and linters
+
+bin/gotestsum: bin/gotestsum-${GOTESTSUM_VERSION}
+	@ln -sf gotestsum-${GOTESTSUM_VERSION} bin/gotestsum
+bin/gotestsum-${GOTESTSUM_VERSION}:
+	@mkdir -p bin
+	curl -L https://github.com/gotestyourself/gotestsum/releases/download/v${GOTESTSUM_VERSION}/gotestsum_${GOTESTSUM_VERSION}_${OS}_amd64.tar.gz | tar -zOxf - gotestsum > ./bin/gotestsum-${GOTESTSUM_VERSION} && chmod +x ./bin/gotestsum-${GOTESTSUM_VERSION}
+
+TEST_PKGS ?= ./...
+.PHONY: test
+test: TEST_FORMAT ?= short
+test: SHELL = /bin/bash
+test: export CGO_ENABLED=1
+test: bin/gotestsum ## Run tests
+	@mkdir -p ${BUILD_DIR}
+	bin/gotestsum --no-summary=skipped --junitfile ${BUILD_DIR}/coverage.xml --format ${TEST_FORMAT} -- -race -coverprofile=${BUILD_DIR}/coverage.txt -covermode=atomic $(filter-out -v,${GOARGS}) $(if ${TEST_PKGS},${TEST_PKGS},./...)
+
+bin/golangci-lint: bin/golangci-lint-${GOLANGCI_VERSION}
+	@ln -sf golangci-lint-${GOLANGCI_VERSION} bin/golangci-lint
+bin/golangci-lint-${GOLANGCI_VERSION}:
+	@mkdir -p bin
+	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b ./bin/ v${GOLANGCI_VERSION}
+	@mv bin/golangci-lint "$@"
+
+.PHONY: lint
+lint: bin/golangci-lint ## Run linter
+	bin/golangci-lint run
+
+.PHONY: fix
+fix: bin/golangci-lint ## Fix lint violations
+	bin/golangci-lint run --fix
+
+# Add custom targets here
+-include custom.mk
+
+.PHONY: list
+list: ## List all make targets
+	@${MAKE} -pRrn : -f $(MAKEFILE_LIST) 2>/dev/null | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' | egrep -v -e '^[^[:alnum:]]' -e '^$@$$' | sort
+
+.PHONY: help
+.DEFAULT_GOAL := help
+help:
+	@grep -h -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
+
+# Variable outputting/exporting rules
+var-%: ; @echo $($*)
+varexport-%: ; @echo $*=$($*)