add github action for yamllint

.github/workflows/push_dockerhub_dev.yml

@@ -27,4 +27,3 @@ jobs:
         run: |
           echo "$DOCKERHUB_PASS" | docker login -u "$DOCKERHUB_USERNAME" --password-stdin
           docker push nfcore/tools:dev
-

.github/workflows/tools-api-docs-release.yml

@@ -9,9 +9,9 @@ jobs:
     runs-on: ubuntu-18.04
     strategy:
       matrix:
-        dir: 
-            - latest
-            - ${{ github.event.release.tag_name }}
+        dir:
+          - latest
+          - ${{ github.event.release.tag_name }}
     steps:
       - name: Check out source-code repository
         uses: actions/checkout@v2

.github/workflows/yaml-lint.yml

@@ -0,0 +1,37 @@
+name: Lint YAML
+on: [push, pull_request]
+jobs:
+  YAML:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions/setup-node@v2
+      - name: Install yaml-lint
+        run: npm install -g yaml-lint
+      - name: Run yaml-lint
+        run: yamllint $(find ${GITHUB_WORKSPACE} -type f -name "*.yml" -o -name "*.yaml") -c ${GITHUB_WORKSPACE}/.yamllint.yml
+
+      # If the above check failed, post a comment on the PR explaining the failure
+      - name: Post PR comment
+        if: failure()
+        uses: mshick/add-pr-comment@v1
+        with:
+          message: |
+            ## YAML linting is failing
+
+            To keep the code consistent with lots of contributors, we run automated code consistency checks.
+            To fix this CI test, please run:
+
+            * Install `yaml-lint`
+                * [Install `npm`](https://www.npmjs.com/get-npm) then [install `yaml-lint`](https://www.npmjs.com/package/yaml-lint) (`npm install -g yaml-lint`)
+            * Fix the markdown errors
+                * Run the test locally: `yamllint $(find . -type f -name "*.yml" -o -name "*.yaml") -c ./.yamllint.yml`
+                * Fix any reported errors in your YAML files
+
+            Once you push these changes the test should pass, and you can hide this comment :+1:
+
+            We highly recommend setting up yaml-lint in your code editor so that this formatting is done automatically on save. Ask about it on Slack for help!
+
+            Thanks again for your contribution!
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          allow-repeats: false

.yamllint.yml

@@ -1,5 +1,6 @@
 extends: default
-
+ignore: |
+    nf_core/*-template/
 rules:
     document-start: disable
     line-length: disable

CHANGELOG.md

@@ -9,6 +9,7 @@
 * Add retry strategy for AWS megatests after releasing [nf-core/tower-action v2.2](https://github.com/nf-core/tower-action/releases/tag/v2.2)
 * Update igenomes path to the `BWAIndex` to fetch the whole `version0.6.0` folder instead of only the `genome.fa` file
 * Remove pinned Node version in the GitHub Actions workflows, to fix errors with `markdownlint`
+* Add yamllint GitHub Action.
 * Add `.yamllint.yml` to avoid line length and document start errors ([#1407](https://github.com/nf-core/tools/issues/1407))
 
 ## General