add CI workflow

Author: stevengj

.github/workflows/ci.yml

@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+    tags: ["*"]
+  pull_request:
+
+jobs:
+  test:
+    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        version:
+          - "1.0"
+          - "1"
+          - "nightly"
+        os:
+          - ubuntu-latest
+          - macOS-latest
+          - windows-latest
+        arch:
+          - x64
+    steps:
+      - uses: actions/checkout@v2
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.version }}
+          arch: ${{ matrix.arch }}
+      - name: Cache artifacts
+        uses: actions/cache@v1
+        env:
+          cache-name: cache-artifacts
+        with:
+          path: ~/.julia/artifacts
+          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-test-${{ env.cache-name }}-
+            ${{ runner.os }}-test-
+            ${{ runner.os }}-
+      - uses: julia-actions/julia-buildpkg@latest
+      - uses: julia-actions/julia-runtest@latest
+      - uses: julia-actions/julia-processcoverage@v1
+      - uses: codecov/codecov-action@v1
+        with:
+          file: ./lcov.info
+          flags: unittests

README.md

@@ -1,5 +1,7 @@
 # StringViews
 
+[![CI](https://github.com/JuliaStrings/StringViews.jl/workflows/CI/badge.svg)](https://github.com/JuliaStrings/StringViews.jl/actions?query=workflow%3ACI)
+
 This Julia package implements a new type of `AbstractString`, a `StringView`,
 that provides a string representation of any underlying array of bytes
 (any `AbstractVector{UInt8}`), interpreted as UTF-8 encoded Unicode data.