Replace GitLab CI with GitHub Actions

.github/workflows/lint.yaml

@@ -0,0 +1,33 @@
+---
+name: Lint
+
+# yamllint disable-line rule:truthy
+on:
+  push:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
+  workflow_dispatch:
+
+jobs:
+  json:
+    name: JSON Lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: ⤵️ Check out code from GitHub
+        uses: actions/checkout@v2.3.4
+      - name: 🚀 Run JQ
+        run: |
+          shopt -s globstar
+          cat **/*.json | jq '.'
+
+  yamllint:
+    name: YAMLLint
+    runs-on: ubuntu-latest
+    steps:
+      - name: ⤵️ Check out code from GitHub
+        uses: actions/checkout@v2.3.4
+      - name: 🚀 Run YAMLLint
+        uses: frenck/action-yamllint@v1.0.2

.gitlab-ci.yml

@@ -1,37 +0,0 @@
----
-image: docker:stable
-
-stages:
-  - linting
-
-.linting: &linting
-  stage: linting
-  tags:
-    - linting
-
-yamllint:
-  <<: *linting
-  image: sdesbure/yamllint
-  before_script:
-    - yamllint --version
-  script:
-    - yamllint .
-
-jsonlint:
-  <<: *linting
-  image: sahsu/docker-jsonlint
-  before_script:
-    - jsonlint --version || true
-  script:
-    - |
-      for file in $(find . -type f -name "*.json"); do
-        if ! jsonlint -q $file; then
-          export FAILED=1
-        else
-          echo "$file OK"
-        fi
-      done
-      if [ "${FAILED}" = "1" ]; then
-        exit 1
-      fi
-