check github actions yamls

.github/workflows/check-config.yml

@@ -1,4 +1,4 @@
-on: 
+on:
   pull_request:
     paths:
       - 'configs/*.json'
@@ -8,8 +8,6 @@ name: Check Config
 jobs:
   check-config:
     runs-on: ubuntu-latest
-    outputs:
-      targets: ${{ steps.set-matrix.outputs.targets }}
     steps:
       - uses: actions/checkout@v2
       - name: check if config files are sorted alphabetically

.github/workflows/check-yaml.yml

@@ -0,0 +1,23 @@
+on:
+  pull_request:
+    paths:
+      - '**/action.yml'
+      - '**/action.yaml'
+      - '**/.github/workflows/*.yml'
+      - '**/.github/workflows/*.yaml'
+
+name: Check YAML
+
+jobs:
+  check-yaml:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      # TODO: switch to mainline once https://github.com/nwisbeta/validate-yaml-schema/pull/21 is merged
+      - uses: galargh/validate-yaml-schema@c8060d4a389d0eec986a90665bf0c496bf1f52e8
+        with:
+          yamlSchemasJson: |
+            {
+              "https://json.schemastore.org/github-action.json": ["**/action.yml", "**/action.yaml"],
+              "https://json.schemastore.org/github-workflow.json": ["**/.github/workflows/*.yml", "**/.github/workflows/*.yaml"]
+            }

README.md

@@ -16,7 +16,7 @@ Some repositories may require some pre-setup steps to be run before tests (or co
 runs:
   using: "composite"
   steps:
-    - name: Step 1 
+    - name: Step 1
       shell: bash
       run: echo "do some initial setup"
     - name: Step 2
@@ -60,5 +60,11 @@ If you want your project to participle, please send a PR!
 
 ## Development
 
+### Branches
+
 The `master` branch contains currently deployed workflows.
 When we make minor changes to these workflows, we don't always want these changes to get deployed to all hundreds of repositories, as this creates a lot of unnecessary noise. Minor changes to the workflows are therefore merged into the [`next`](https://github.com/protocol/.github/tree/next) branch. When the time has come, we create a PR from the `next` branch to `master` to trigger a deployment to all repositores.
+
+### IDE
+
+If you're using [Visual Studio Code](https://code.visualstudio.com/) for development, you might want to install the [YAML](https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml) extension. It is configured to perform GitHub workflow/action linting out-of-the-box. If you're using a different IDE, you can check if a [client](https://github.com/redhat-developer/yaml-language-server#clients) for it exists.

templates/.github/workflows/go-test.yml

@@ -10,8 +10,8 @@ jobs:
         go: [ "1.16.x", "1.17.x" ]
     env:
       COVERAGES: ""
-    runs-on: ${{ matrix.os }}-latest
-    name: ${{ matrix.os}} (go ${{ matrix.go }})
+    runs-on: ${{ format('${0}-latest', matrix.os) }}
+    name: ${{ matrix.os }} (go ${{ matrix.go }})
     steps:
       - uses: actions/checkout@v2
         with: