Add remark-gfm to workflow job

.github/workflows/remark.yml

@@ -22,7 +22,7 @@ jobs:
       uses: actions/setup-node@v1.4.4
 
     - name: Install remark
-      run: npm install remark-cli remark-lint remark-lint-maximum-line-length remark-preset-lint-recommended
+      run: npm install remark-cli remark-lint remark-lint-maximum-line-length remark-preset-lint-recommended remark-gfm
 
     # Run
     - name: Check *.md files

.remarkrc

@@ -1,6 +1,7 @@
 {
   "plugins": [
     "remark-preset-lint-recommended",
+    "remark-gfm",
     ["remark-lint-list-item-indent", false],
     ["remark-lint-no-literal-urls", false],
     ["remark-lint-no-shortcut-reference-link", false],