Delete security.yml

See https://github.com/searxng/searxng/pull/1730

.github/workflows/security.yml

@@ -1,27 +0,0 @@
-name: "Security checks"
-on:
-  schedule:
-    - cron: "05 06 * * *"
-  workflow_dispatch:
-
-jobs:
-  dockers:
-    name: Trivy ${{ matrix.image }}
-    runs-on: ubuntu-20.04
-    strategy:
-      fail-fast: false
-      matrix:
-        image: ["searxng/searxng", "dalf/filtron", "dalf/morty"]
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Run Trivy vulnerability scanner
-        uses: aquasecurity/trivy-action@master
-        with:
-          image-ref: '${{ matrix.image }}:latest'
-          format: 'table'
-          exit-code: '1'
-          ignore-unfixed: false
-          vuln-type: 'os,library'
-          severity: 'UNKNOWN,LOW,MEDIUM,HIGH,CRITICAL'