fix(cli): cli output crashes if script closing tag is in the spec

fixes #563

cli/index.ts

@@ -236,7 +236,7 @@ async function getPageHTML(
     redocHTML: `
     <div id="redoc">${(ssr && html) || ''}</div>
     <script>
-    ${(ssr && `const __redoc_state = ${escapeUnicode(JSON.stringify(state))};`) || ''}
+    ${(ssr && `const __redoc_state = ${sanitizeJSONString(JSON.stringify(state))};`) || ''}
 
     var container = document.getElementById('redoc');
     Redoc.${
@@ -306,6 +306,15 @@ function isURL(str: string): boolean {
   return /^(https?:)\/\//m.test(str);
 }
 
+function sanitizeJSONString(str: string) {
+  return escapeClosingScriptTag(escapeUnicode(str));
+}
+
+// see http://www.thespanner.co.uk/2011/07/25/the-json-specification-is-now-wrong/
+function escapeClosingScriptTag(str) {
+  return str.replace(/<\/script>/g, '<\\/script>');
+}
+
 // see http://www.thespanner.co.uk/2011/07/25/the-json-specification-is-now-wrong/
 function escapeUnicode(str) {
   return str.replace(/\u2028|\u2029/g, m => '\\u202' + (m === '\u2028' ? '8' : '9'));