ci: Remove skipci job

.github/workflows/dev-image.yml

@@ -22,14 +22,8 @@ on:
       - 'Makefile'
 
 jobs:
-  skipci:
-    runs-on: ubuntu-18.04
-    steps:
-      - run: echo "[skip ci] ${{ contains(github.event.head_commit.message, '[skip ci]') }}"
-
   dev-image-test:
     runs-on: ubuntu-18.04
-    if: contains(github.event.head_commit.message, '[skip ci]') == false
     steps:
       - uses: actions/checkout@v2
       - run: make build