n-api: bump version of n-api supported

Bump the version due to additions to the api.

PR-URL: nodejs#19497
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

src/node_version.h

@@ -62,6 +62,6 @@
 #define NODE_MODULE_VERSION 48 /* Node.js v6.0.0 */
 
 // the NAPI_VERSION provided by this version of the runtime
-#define NAPI_VERSION  2
+#define NAPI_VERSION  3
 
 #endif  // SRC_NODE_VERSION_H_

test/addons-napi/test_general/test.js

@@ -32,9 +32,9 @@ assert.strictEqual(test_general.testGetPrototype(extendedObject),
 assert.notStrictEqual(test_general.testGetPrototype(baseObject),
                       test_general.testGetPrototype(extendedObject));
 
-// test version management funcitons
-// expected version is currently 1
-assert.strictEqual(test_general.testGetVersion(), 2);
+// test version management functions
+// expected version is currently 3
+assert.strictEqual(test_general.testGetVersion(), 3);
 
 const [ major, minor, patch, release ] = test_general.testGetNodeVersion();
 assert.strictEqual(process.version.split('-')[0],