chore: Update dependabot ignore list

.github/dependabot.yml

@@ -20,22 +20,23 @@ updates:
         versions: ['>=8.0.0']
       - dependency-name: rand-user-agent
         versions: ['>=2.0.1']
-      - dependency-name: remark
-        versions: ['>=14.0.0']
-      - dependency-name: remark-frontmatter
-        versions: ['>=4.0.0']
-      - dependency-name: remark-gfm
-        versions: ['>=2.0.0']
       - dependency-name: remark-parse
         versions: ['>=10.0.0']
       - dependency-name: remark-preset-prettier
         versions: ['>=1.0.0']
-      - dependency-name: remark-stringify
-        versions: ['>=10.0.0']
-      - dependency-name: string-width
-        versions: ['>=5.0.0']
       - dependency-name: unified
         versions: ['>=10.0.0']
+    # remark-custom-heading-id is not updated to
+    # the latest mdast/mdxast which is released from
+    # the second half of 2023
+      - dependency-name: remark
+        versions: ['>=15.0.0']
+      - dependency-name: remark-frontmatter
+        versions: ['>=5.0.0']
+      - dependency-name: remark-gfm
+        versions: ['>=4.0.0']
+      - dependency-name: remark-mdx
+        versions: ['>=3.0.0']
 
   - package-ecosystem: npm
     directory: '/website'