Bump markdown-it-attrs from 3.0.3 to 4.0.0

Bumps [markdown-it-attrs](https://github.com/arve0/markdown-it-attrs) from 3.0.3 to 4.0.0.
- [Release notes](https://github.com/arve0/markdown-it-attrs/releases)
- [Commits](https://github.com/arve0/markdown-it-attrs/compare/v3.0.3...v4.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -22,7 +22,7 @@
     "@vuepress/plugin-back-to-top": "1.7.1",
     "@vuepress/plugin-medium-zoom": "1.7.1",
     "jsdom": "16.4.0",
-    "markdown-it-attrs": "3.0.3",
+    "markdown-it-attrs": "4.0.0",
     "pre-commit": "1.2.2",
     "prettier": "2.2.1",
     "vuepress": "1.7.1"

yarn.lock

@@ -4972,10 +4972,10 @@ markdown-it-anchor@^5.0.2:
   resolved "https://registry.yarnpkg.com/markdown-it-anchor/-/markdown-it-anchor-5.3.0.tgz#d549acd64856a8ecd1bea58365ef385effbac744"
   integrity sha512-/V1MnLL/rgJ3jkMWo84UR+K+jF1cxNG1a+KwqeXqTIJ+jtA8aWSHuigx8lTzauiIjBDbwF3NcWQMotd0Dm39jA==
 
-markdown-it-attrs@3.0.3:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/markdown-it-attrs/-/markdown-it-attrs-3.0.3.tgz#92acdb16fe551cb056c5eb9848413443cafb5231"
-  integrity sha512-cLnICU2t61skNCr4Wih/sdza+UbQcqJGZwvqAypnbWA284nzDm+Gpc90iaRk/JjsIy4emag5v3s0rXFhFBWhCA==
+markdown-it-attrs@4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/markdown-it-attrs/-/markdown-it-attrs-4.0.0.tgz#eadae3ea0c7d17c5e83b98a4ec95a47f4e4960f5"
+  integrity sha512-uLjtdCmhhmL3BuZsReYkFxk74qKjj5ahe34teBpOCJ4hYZZl7/ftLyXWLowngC2moRkbLEvKwN/7TMwbhbHE/A==
 
 markdown-it-chain@^1.3.0:
   version "1.3.0"