Bump sanitize-html from 1.20.1 to 1.21.1 (#66)

Bumps [sanitize-html](https://github.com/punkave/sanitize-html) from 1.20.1 to 1.21.1.
- [Release notes](https://github.com/punkave/sanitize-html/releases)
- [Changelog](https://github.com/apostrophecms/sanitize-html/blob/master/CHANGELOG.md)
- [Commits](https://github.com/punkave/sanitize-html/commits/1.21.1)

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

package-lock.json

@@ -1920,12 +1920,24 @@
       "integrity": "sha1-6oCxBqh1OHdOijpKWv4pPeSJ4Kk="
     },
     "dom-serializer": {
-      "version": "0.1.1",
-      "resolved": "https://registry.npmjs.org/dom-serializer/-/dom-serializer-0.1.1.tgz",
-      "integrity": "sha512-l0IU0pPzLWSHBcieZbpOKgkIn3ts3vAh7ZuFyXNwJxJXk/c4Gwj9xaTJwIDVQCXawWD0qb3IzMGH5rglQaO0XA==",
+      "version": "0.2.2",
+      "resolved": "https://registry.npmjs.org/dom-serializer/-/dom-serializer-0.2.2.tgz",
+      "integrity": "sha512-2/xPb3ORsQ42nHYiSunXkDjPLBaEj/xTwUO4B7XCZQTRk7EBtTOPaygh10YAAh2OI1Qrp6NWfpAhzswj0ydt9g==",
       "requires": {
-        "domelementtype": "^1.3.0",
-        "entities": "^1.1.1"
+        "domelementtype": "^2.0.1",
+        "entities": "^2.0.0"
+      },
+      "dependencies": {
+        "domelementtype": {
+          "version": "2.0.1",
+          "resolved": "https://registry.npmjs.org/domelementtype/-/domelementtype-2.0.1.tgz",
+          "integrity": "sha512-5HOHUDsYZWV8FGWN0Njbr/Rn7f/eWSQi1v7+HsUVwXgn8nWWlL64zKDkS0n8ZmQ3mlWOMuXOnR+7Nx/5tMO5AQ=="
+        },
+        "entities": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/entities/-/entities-2.0.0.tgz",
+          "integrity": "sha512-D9f7V0JSRwIxlRI2mjMqufDrRDnx8p+eEOz7aUM9SuvF8gsBzra0/6tbjl1m8eQHrZlYj6PxqE00hZ1SAIKPLw=="
+        }
       }
     },
     "domelementtype": {
@@ -5862,9 +5874,9 @@
       "integrity": "sha1-AerA/jta9xoqbAL+q7jB/vfgDqs="
     },
     "postcss": {
-      "version": "7.0.17",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-7.0.17.tgz",
-      "integrity": "sha512-546ZowA+KZ3OasvQZHsbuEpysvwTZNGJv9EfyCQdsIDltPSWHAeTQ5fQy/Npi2ZDtLI3zs7Ps/p6wThErhm9fQ==",
+      "version": "7.0.26",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-7.0.26.tgz",
+      "integrity": "sha512-IY4oRjpXWYshuTDFxMVkJDtWIk2LhsTlu8bZnbEJA4+bYT16Lvpo8Qv6EvDumhYRgzjZl489pmsY3qVgJQ08nA==",
       "requires": {
         "chalk": "^2.4.2",
         "source-map": "^0.6.1",
@@ -6545,9 +6557,9 @@
       "integrity": "sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg=="
     },
     "sanitize-html": {
-      "version": "1.20.1",
-      "resolved": "https://registry.npmjs.org/sanitize-html/-/sanitize-html-1.20.1.tgz",
-      "integrity": "sha512-txnH8TQjaQvg2Q0HY06G6CDJLVYCpbnxrdO0WN8gjCKaU5J0KbyGYhZxx5QJg3WLZ1lB7XU9kDkfrCXUozqptA==",
+      "version": "1.21.1",
+      "resolved": "https://registry.npmjs.org/sanitize-html/-/sanitize-html-1.21.1.tgz",
+      "integrity": "sha512-W6enXSVphVaVbmVbzVngBthR5f5sMmhq3EfPfBlzBzp2WnX8Rnk7NGpP7KmHUc0Y3MVk9tv/+CbpdHchX9ai7g==",
       "requires": {
         "chalk": "^2.4.1",
         "htmlparser2": "^3.10.0",