Implement "check-latest" flag to check if pre-cached version is lates…

…t one (actions#186)

.github/workflows/check-dist.yml

@@ -24,7 +24,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Set Node.js 12.x
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v2
         with:
           node-version: 12.x
 

.github/workflows/licensed.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Install licensed
         run: |
           cd $RUNNER_TEMP
-          curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/2.12.2/licensed-2.12.2-linux-x64.tar.gz
+          curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/3.3.1/licensed-3.3.1-linux-x64.tar.gz
           sudo tar -xzf licensed.tar.gz
           sudo mv licensed /usr/local/bin/licensed
       - run: licensed status

.github/workflows/versions.yml

@@ -33,6 +33,23 @@ jobs:
         run: __tests__/verify-go.sh ${{ matrix.go }}
         shell: bash
 
+  check-latest:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        go-version: [1.16, 1.17]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup Go and check latest
+        uses: ./
+        with:
+          go-version: ${{ matrix.go-version }}
+          check-latest: true
+      - name: Verify Go
+        run: go version
+
   setup-versions-from-manifest:
     name: Setup ${{ matrix.go }} ${{ matrix.os }}
     runs-on: ${{ matrix.os }}

.github/workflows/workflow.yml

@@ -25,8 +25,8 @@ jobs:
           node-version: 12
           cache: npm
 
-      - name: npm install
-        run: npm install
+      - name: npm ci
+        run: npm ci
 
       - name: Lint
         run: npm run format-check

README.md

@@ -16,10 +16,11 @@ This action sets up a go environment for use in actions by:
 The V2 offers:
 - Adds GOBIN to the PATH
 - Proxy Support
-- stable input 
+- `stable` input 
+- Check latest version
 - Bug Fixes (including issues around version matching and semver)
 
-It will first check the local cache for a version match. If version is not found locally, It will pull it from `main` branch of [go-versions](https://github.com/actions/go-versions/blob/main/versions-manifest.json) repository and on miss or failure, it will fall back to the previous behavior of download directly from [go dist](https://storage.googleapis.com/golang).
+The action will first check the local cache for a version match. If a version is not found locally, it will pull it from the `main` branch of the [go-versions](https://github.com/actions/go-versions/blob/main/versions-manifest.json) repository. On miss or failure, it will fall back to downloading directly from [go dist](https://storage.googleapis.com/golang). To change the default behavior, please use the [check-latest input](#check-latest-version).
 
 Matching by [semver spec](https://github.com/npm/node-semver):
 ```yaml
@@ -46,17 +47,36 @@ steps:
 
 See [action.yml](action.yml)
 
-Basic:
+## Basic:
 ```yaml
 steps:
-  - uses: actions/checkout@master
+  - uses: actions/checkout@v2
+  - uses: actions/setup-go@v2
+    with:
+      go-version: '1.16.1' # The Go version to download (if necessary) and use.
+  - run: go run hello.go
+```
+
+
+## Check latest version:  
+
+The `check-latest` flag defaults to `false`. Use the default or set `check-latest` to `false` if you prefer stability and if you want to ensure a specific Go version is always used.
+
+If `check-latest` is set to `true`, the action first checks if the cached version is the latest one. If the locally cached version is not the most up-to-date, a Go version will then be downloaded. Set `check-latest` to `true` if you want the most up-to-date Go version to always be used.
+
+> Setting `check-latest` to `true` has performance implications as downloading Go versions is slower than using cached versions.
+
+```yaml
+steps:
+  - uses: actions/checkout@v2
   - uses: actions/setup-go@v2
     with:
-      go-version: '1.9.3' # The Go version to download (if necessary) and use.
+      go-version: '1.14'
+      check-latest: true
   - run: go run hello.go
 ```
 
-Matrix Testing:
+## Matrix Testing:
 ```yaml
 jobs:
   build:

__tests__/data/versions-manifest.json

@@ -1,4 +1,29 @@
 [
+    {
+      "version": "1.17.6",
+      "stable": true,
+      "release_url": "https://github.com/actions/go-versions/releases/tag/1.17.6-1668090892",
+      "files": [
+        {
+          "filename": "go-1.17.6-darwin-x64.tar.gz",
+          "arch": "x64",
+          "platform": "darwin",
+          "download_url": "https://github.com/actions/go-versions/releases/download/1.17.6-1668090892/go-1.17.6-darwin-x64.tar.gz"
+        },
+        {
+          "filename": "go-1.17.6-linux-x64.tar.gz",
+          "arch": "x64",
+          "platform": "linux",
+          "download_url": "https://github.com/actions/go-versions/releases/download/1.17.6-1668090892/go-1.17.6-linux-x64.tar.gz"
+        },
+        {
+          "filename": "go-1.17.6-win32-x64.zip",
+          "arch": "x64",
+          "platform": "win32",
+          "download_url": "https://github.com/actions/go-versions/releases/download/1.17.6-1668090892/go-1.17.6-win32-x64.zip"
+        }
+      ]
+    },
     {
       "version": "1.12.17",
       "stable": true,