Merge branch 'master' of github.com:usablica/intro.js

* 'master' of github.com:usablica/intro.js:
  Add available since tags for hints API docs
  Added a valid SPDX license

Author: afshinm

docs/docs/hints/api.md

@@ -114,6 +114,8 @@ introJs().addHints();
 
 Show the hint with given `hintId`.
 
+**Available since**: v2.4.0
+
 **Example:**
 ```javascript
 introJs().showHint(1);
@@ -125,6 +127,8 @@ introJs().showHint(1);
 
 Show all hints.
 
+**Available since**: v2.4.0
+
 **Example:**
 ```javascript
 introJs().showHints();

package.json

@@ -15,7 +15,7 @@
     "node >=0.1.90"
   ],
   "main": "intro.js",
-  "license": "See LICENSE.md",
+  "license": "AGPL-3.0",
   "spm": {
     "main": "intro.js",
     "output": [