Add dependabot/codeql/mergify (#691)

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

.github/dependabot.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "daily"
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/mergify.yml

@@ -0,0 +1,8 @@
+pull_request_rules:
+  - name: automatic merge for dependabot pull requests
+    conditions:
+      - author~=^dependabot(|-preview)\[bot\]$
+    actions:
+      merge:
+        method: squash
+        commit_message: title+body

.github/workflows/codeql.yml

@@ -0,0 +1,32 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  codeql-analyze:
+    name: CodeQL Analyze
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'javascript' ]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2.3.4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: javascript
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v1
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1