Bump posthtml from 0.16.6 to 0.16.7 (#3962)

Author: zachleat

package-lock.json

@@ -160,7 +160,7 @@
 		"nunjucks": "^3.2.4",
 		"picomatch": "^4.0.3",
 		"please-upgrade-node": "^3.2.0",
-		"posthtml": "^0.16.6",
+		"posthtml": "^0.16.7",
 		"posthtml-match-helper": "^2.0.3",
 		"semver": "^7.7.3",
 		"tinyglobby": "^0.2.15"