Add linter.

.github/workflows/snapshot.yml

@@ -1,28 +1,45 @@
 name: Snapshot
 
-on:
+"on":
   push:
     branches:
-    - 'main'
-    - '[1-9]+.[0-9]+.x'
+      - 'main'
+      - '[1-9]+.[0-9]+.x'
 
 jobs:
-  build:
+
+  lint-yaml:
     runs-on: ubuntu-latest
     steps:
-    - name: checkout
-      uses: actions/checkout@v2
-    - name: setup
-      uses: actions/setup-java@v1
-      with:
-        java-version: 11
-        server-id: sonatype-nexus
-        server-username: SERVER_USERNAME
-        server-password: SERVER_PASSWORD
-    - name: dependencies
-      run: mvn -B -q dependency:go-offline
-    - name: deploy
-      run: mvn -B deploy
-      env:
-        SERVER_USERNAME: ${{ secrets.SONATYPE_NEXUS_USERNAME }}
-        SERVER_PASSWORD: ${{ secrets.SONATYPE_NEXUS_PASSWORD }}
+      - uses: actions/checkout@v2
+      - uses: ibiqlik/action-yamllint@v3
+        with:
+          format: colored
+          strict: true
+
+  lint-markdown:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: docker://avtodev/markdown-lint:v1
+        with:
+          args: /github/workspace
+
+  build:
+    runs-on: ubuntu-latest
+    needs:
+      - lint-markdown
+      - lint-yaml
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 11
+          server-id: sonatype-nexus
+          server-username: SERVER_USERNAME
+          server-password: SERVER_PASSWORD
+      - run: mvn -B dependency:go-offline -q
+      - run: mvn -B deploy -Poss
+        env:
+          SERVER_USERNAME: ${{ secrets.SONATYPE_NEXUS_USERNAME }}
+          SERVER_PASSWORD: ${{ secrets.SONATYPE_NEXUS_PASSWORD }}