Fix npm script call

Author: ArtyomVancyan

Diff for: tox.ini

@@ -10,20 +10,20 @@ commands =
     npm install
     npm install -D @types/react@^16.0.0
     npm test
-    npm build
+    npm run build
 
 [testenv:rc17]
 allowlist_externals = npm
 commands =
     npm install
     npm install -D @types/react@^17.0.0
     npm test
-    npm build
+    npm run build
 
 [testenv:rc18]
 allowlist_externals = npm
 commands =
     npm install
     npm install -D @types/react@^18.0.0
     npm test
-    npm build
+    npm run build