fix: decode single quotes in html attributes (vuejs#9341)

Author: bughit

src/compiler/parser/html-parser.js

@@ -36,10 +36,11 @@ const decodingMap = {
   '"': '"',
   '&': '&',
   '
': '\n',
-  '	': '\t'
+  '	': '\t',
+  ''': "'"
 }
-const encodedAttr = /&(?:lt|gt|quot|amp);/g
-const encodedAttrWithNewLines = /&(?:lt|gt|quot|amp|#10|#9);/g
+const encodedAttr = /&(?:lt|gt|quot|amp|#39);/g
+const encodedAttrWithNewLines = /&(?:lt|gt|quot|amp|#39|#10|#9);/g
 
 // #5992
 const isIgnoreNewlineTag = makeMap('pre,textarea', true)